Hammering / knocking noise on 4.0L6 '99 Cherokee
 

I would say, I have a severe case of piston slap, but from what I have
found out about the infamouspiston slap problem, it should have ended
long before 1999.
So, what problem do I have on my '99 Cherokee? The symptoms are very
similar to the legendary piston slap:
Symptoms vary from no noise, to a light ticking, to a
ticking/hammering to a
strong and very audible hammering/knocking noise. The noise is
generally more pronounced at start up, when the engine is cold.
Sometimes, the noise disappears when the engine warms up.
Sometimes, when the noise appears at start up, stopping and
immediately restarting the engine stops the noise completely.
The symptom is most noticeable during idle, but will get louder as
engine speed increases, and sometimes appears / disappears randomly on
a warm engine and at various driving conditions.
While this noise was very infrequent before, now it is a almost daily
occurrence.

The engine has about 60K and was serviced regularly at the local
dealer, with
oil and Mopar filter changes every 3,000 Miles. The engine runs,
starts,
and idles otherwise completely fine. No significant oil consumption
either.

The dealer here in Thailand suggests to open up the engine, and
perhaps change the hydraulic lifter, but he is basically not really
sure, what causes the problem.

I have used a Fuel Injector Cleaner without success.

Most likely, it is not the piston slap problem, as the car is built in
1999.
If it is the lifter, why stopping and restarting the engine clears the
noise
immediately sometimes, but not all the time.
The noise appears at a cold engine and on a warm engine as well, and
during idle but during normal driving conditions as well, but
randomly, it seems. If drive at high rpm, there is generally no noise.

What could cause that noise?

Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Interesting....

The last time I heard those symptoms was on the first start up of a
fresh rebuild and we both just about ---- ourselves we were so pissed
off. We restarted it and no noise or low, then creeping back up. 3rd
time knock knock.

Then as we are leaning over to try and listen where it was coming from,
I put my hand on the alternator and almost got burned it was so hot.
Bingo, the alternator had decided to give up and something inside was
slamming around.

We then used an automotive stethoscope to confirm it. Basically a thin
metal rod with a clear plastic hose on one end. The hose goes to the
ear and you can really trace down a knock with one.

I would be making or using one before spending money. Even your finger
touching parts can sometimes nail it.

One other cause of a strange knock is a worn clutch on the rad fan.
This can change every start up and usually is temperature dependent as
the clutch changes when hot.

With the engine cold and off, I would try moving the rad fan around for
play or clicks.

I would then heat it up good and watch when someone shuts down the
engine. If the fan keeps spinning after a hot shutdown, the clutch is
baked. It should stop almost immediately.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> I would say, I have a severe case of piston slap, but from what I have
> found out about the infamouspiston slap problem, it should have ended
> long before 1999.
> So, what problem do I have on my '99 Cherokee? The symptoms are very
> similar to the legendary piston slap:
> Symptoms vary from no noise, to a light ticking, to a
> ticking/hammering to a
> strong and very audible hammering/knocking noise. The noise is
> generally more pronounced at start up, when the engine is cold.
> Sometimes, the noise disappears when the engine warms up.
> Sometimes, when the noise appears at start up, stopping and
> immediately restarting the engine stops the noise completely.
> The symptom is most noticeable during idle, but will get louder as
> engine speed increases, and sometimes appears / disappears randomly on
> a warm engine and at various driving conditions.
> While this noise was very infrequent before, now it is a almost daily
> occurrence.
>
> The engine has about 60K and was serviced regularly at the local
> dealer, with
> oil and Mopar filter changes every 3,000 Miles. The engine runs,
> starts,
> and idles otherwise completely fine. No significant oil consumption
> either.
>
> The dealer here in Thailand suggests to open up the engine, and
> perhaps change the hydraulic lifter, but he is basically not really
> sure, what causes the problem.
>
> I have used a Fuel Injector Cleaner without success.
>
> Most likely, it is not the piston slap problem, as the car is built in
> 1999.
> If it is the lifter, why stopping and restarting the engine clears the
> noise
> immediately sometimes, but not all the time.
> The noise appears at a cold engine and on a warm engine as well, and
> during idle but during normal driving conditions as well, but
> randomly, it seems. If drive at high rpm, there is generally no noise.
>
> What could cause that noise?
>
> Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Interesting....

The last time I heard those symptoms was on the first start up of a
fresh rebuild and we both just about ---- ourselves we were so pissed
off. We restarted it and no noise or low, then creeping back up. 3rd
time knock knock.

Then as we are leaning over to try and listen where it was coming from,
I put my hand on the alternator and almost got burned it was so hot.
Bingo, the alternator had decided to give up and something inside was
slamming around.

We then used an automotive stethoscope to confirm it. Basically a thin
metal rod with a clear plastic hose on one end. The hose goes to the
ear and you can really trace down a knock with one.

I would be making or using one before spending money. Even your finger
touching parts can sometimes nail it.

One other cause of a strange knock is a worn clutch on the rad fan.
This can change every start up and usually is temperature dependent as
the clutch changes when hot.

With the engine cold and off, I would try moving the rad fan around for
play or clicks.

I would then heat it up good and watch when someone shuts down the
engine. If the fan keeps spinning after a hot shutdown, the clutch is
baked. It should stop almost immediately.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> I would say, I have a severe case of piston slap, but from what I have
> found out about the infamouspiston slap problem, it should have ended
> long before 1999.
> So, what problem do I have on my '99 Cherokee? The symptoms are very
> similar to the legendary piston slap:
> Symptoms vary from no noise, to a light ticking, to a
> ticking/hammering to a
> strong and very audible hammering/knocking noise. The noise is
> generally more pronounced at start up, when the engine is cold.
> Sometimes, the noise disappears when the engine warms up.
> Sometimes, when the noise appears at start up, stopping and
> immediately restarting the engine stops the noise completely.
> The symptom is most noticeable during idle, but will get louder as
> engine speed increases, and sometimes appears / disappears randomly on
> a warm engine and at various driving conditions.
> While this noise was very infrequent before, now it is a almost daily
> occurrence.
>
> The engine has about 60K and was serviced regularly at the local
> dealer, with
> oil and Mopar filter changes every 3,000 Miles. The engine runs,
> starts,
> and idles otherwise completely fine. No significant oil consumption
> either.
>
> The dealer here in Thailand suggests to open up the engine, and
> perhaps change the hydraulic lifter, but he is basically not really
> sure, what causes the problem.
>
> I have used a Fuel Injector Cleaner without success.
>
> Most likely, it is not the piston slap problem, as the car is built in
> 1999.
> If it is the lifter, why stopping and restarting the engine clears the
> noise
> immediately sometimes, but not all the time.
> The noise appears at a cold engine and on a warm engine as well, and
> during idle but during normal driving conditions as well, but
> randomly, it seems. If drive at high rpm, there is generally no noise.
>
> What could cause that noise?
>
> Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Interesting....

The last time I heard those symptoms was on the first start up of a
fresh rebuild and we both just about ---- ourselves we were so pissed
off. We restarted it and no noise or low, then creeping back up. 3rd
time knock knock.

Then as we are leaning over to try and listen where it was coming from,
I put my hand on the alternator and almost got burned it was so hot.
Bingo, the alternator had decided to give up and something inside was
slamming around.

We then used an automotive stethoscope to confirm it. Basically a thin
metal rod with a clear plastic hose on one end. The hose goes to the
ear and you can really trace down a knock with one.

I would be making or using one before spending money. Even your finger
touching parts can sometimes nail it.

One other cause of a strange knock is a worn clutch on the rad fan.
This can change every start up and usually is temperature dependent as
the clutch changes when hot.

With the engine cold and off, I would try moving the rad fan around for
play or clicks.

I would then heat it up good and watch when someone shuts down the
engine. If the fan keeps spinning after a hot shutdown, the clutch is
baked. It should stop almost immediately.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> I would say, I have a severe case of piston slap, but from what I have
> found out about the infamouspiston slap problem, it should have ended
> long before 1999.
> So, what problem do I have on my '99 Cherokee? The symptoms are very
> similar to the legendary piston slap:
> Symptoms vary from no noise, to a light ticking, to a
> ticking/hammering to a
> strong and very audible hammering/knocking noise. The noise is
> generally more pronounced at start up, when the engine is cold.
> Sometimes, the noise disappears when the engine warms up.
> Sometimes, when the noise appears at start up, stopping and
> immediately restarting the engine stops the noise completely.
> The symptom is most noticeable during idle, but will get louder as
> engine speed increases, and sometimes appears / disappears randomly on
> a warm engine and at various driving conditions.
> While this noise was very infrequent before, now it is a almost daily
> occurrence.
>
> The engine has about 60K and was serviced regularly at the local
> dealer, with
> oil and Mopar filter changes every 3,000 Miles. The engine runs,
> starts,
> and idles otherwise completely fine. No significant oil consumption
> either.
>
> The dealer here in Thailand suggests to open up the engine, and
> perhaps change the hydraulic lifter, but he is basically not really
> sure, what causes the problem.
>
> I have used a Fuel Injector Cleaner without success.
>
> Most likely, it is not the piston slap problem, as the car is built in
> 1999.
> If it is the lifter, why stopping and restarting the engine clears the
> noise
> immediately sometimes, but not all the time.
> The noise appears at a cold engine and on a warm engine as well, and
> during idle but during normal driving conditions as well, but
> randomly, it seems. If drive at high rpm, there is generally no noise.
>
> What could cause that noise?
>
> Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Hi Robert,
If it ever sounds like a ticking then I vote with your dealer and
say you need a new set of lifters. But if it does sound like a hammer
beating the side of the block, then it could be piston slap, but usually
that won't go away with oil pressure and warm up, and will at a certain
RPM be more pronounced. I think your describing main bearings, their
worn clearances let the oil drain out during the time it sits, and
knocks until they are lubed again. I think it time to take it apart and
find the problem while you still have a core.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Robert Goldpalm wrote:
>
> I would say, I have a severe case of piston slap, but from what I have
> found out about the infamouspiston slap problem, it should have ended
> long before 1999.
> So, what problem do I have on my '99 Cherokee? The symptoms are very
> similar to the legendary piston slap:
> Symptoms vary from no noise, to a light ticking, to a
> ticking/hammering to a
> strong and very audible hammering/knocking noise. The noise is
> generally more pronounced at start up, when the engine is cold.
> Sometimes, the noise disappears when the engine warms up.
> Sometimes, when the noise appears at start up, stopping and
> immediately restarting the engine stops the noise completely.
> The symptom is most noticeable during idle, but will get louder as
> engine speed increases, and sometimes appears / disappears randomly on
> a warm engine and at various driving conditions.
> While this noise was very infrequent before, now it is a almost daily
> occurrence.
>
> The engine has about 60K and was serviced regularly at the local
> dealer, with
> oil and Mopar filter changes every 3,000 Miles. The engine runs,
> starts,
> and idles otherwise completely fine. No significant oil consumption
> either.
>
> The dealer here in Thailand suggests to open up the engine, and
> perhaps change the hydraulic lifter, but he is basically not really
> sure, what causes the problem.
>
> I have used a Fuel Injector Cleaner without success.
>
> Most likely, it is not the piston slap problem, as the car is built in
> 1999.
> If it is the lifter, why stopping and restarting the engine clears the
> noise
> immediately sometimes, but not all the time.
> The noise appears at a cold engine and on a warm engine as well, and
> during idle but during normal driving conditions as well, but
> randomly, it seems. If drive at high rpm, there is generally no noise.
>
> What could cause that noise?
>
> Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Hi Robert,
If it ever sounds like a ticking then I vote with your dealer and
say you need a new set of lifters. But if it does sound like a hammer
beating the side of the block, then it could be piston slap, but usually
that won't go away with oil pressure and warm up, and will at a certain
RPM be more pronounced. I think your describing main bearings, their
worn clearances let the oil drain out during the time it sits, and
knocks until they are lubed again. I think it time to take it apart and
find the problem while you still have a core.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Robert Goldpalm wrote:
>
> I would say, I have a severe case of piston slap, but from what I have
> found out about the infamouspiston slap problem, it should have ended
> long before 1999.
> So, what problem do I have on my '99 Cherokee? The symptoms are very
> similar to the legendary piston slap:
> Symptoms vary from no noise, to a light ticking, to a
> ticking/hammering to a
> strong and very audible hammering/knocking noise. The noise is
> generally more pronounced at start up, when the engine is cold.
> Sometimes, the noise disappears when the engine warms up.
> Sometimes, when the noise appears at start up, stopping and
> immediately restarting the engine stops the noise completely.
> The symptom is most noticeable during idle, but will get louder as
> engine speed increases, and sometimes appears / disappears randomly on
> a warm engine and at various driving conditions.
> While this noise was very infrequent before, now it is a almost daily
> occurrence.
>
> The engine has about 60K and was serviced regularly at the local
> dealer, with
> oil and Mopar filter changes every 3,000 Miles. The engine runs,
> starts,
> and idles otherwise completely fine. No significant oil consumption
> either.
>
> The dealer here in Thailand suggests to open up the engine, and
> perhaps change the hydraulic lifter, but he is basically not really
> sure, what causes the problem.
>
> I have used a Fuel Injector Cleaner without success.
>
> Most likely, it is not the piston slap problem, as the car is built in
> 1999.
> If it is the lifter, why stopping and restarting the engine clears the
> noise
> immediately sometimes, but not all the time.
> The noise appears at a cold engine and on a warm engine as well, and
> during idle but during normal driving conditions as well, but
> randomly, it seems. If drive at high rpm, there is generally no noise.
>
> What could cause that noise?
>
> Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Hi Robert,
If it ever sounds like a ticking then I vote with your dealer and
say you need a new set of lifters. But if it does sound like a hammer
beating the side of the block, then it could be piston slap, but usually
that won't go away with oil pressure and warm up, and will at a certain
RPM be more pronounced. I think your describing main bearings, their
worn clearances let the oil drain out during the time it sits, and
knocks until they are lubed again. I think it time to take it apart and
find the problem while you still have a core.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Robert Goldpalm wrote:
>
> I would say, I have a severe case of piston slap, but from what I have
> found out about the infamouspiston slap problem, it should have ended
> long before 1999.
> So, what problem do I have on my '99 Cherokee? The symptoms are very
> similar to the legendary piston slap:
> Symptoms vary from no noise, to a light ticking, to a
> ticking/hammering to a
> strong and very audible hammering/knocking noise. The noise is
> generally more pronounced at start up, when the engine is cold.
> Sometimes, the noise disappears when the engine warms up.
> Sometimes, when the noise appears at start up, stopping and
> immediately restarting the engine stops the noise completely.
> The symptom is most noticeable during idle, but will get louder as
> engine speed increases, and sometimes appears / disappears randomly on
> a warm engine and at various driving conditions.
> While this noise was very infrequent before, now it is a almost daily
> occurrence.
>
> The engine has about 60K and was serviced regularly at the local
> dealer, with
> oil and Mopar filter changes every 3,000 Miles. The engine runs,
> starts,
> and idles otherwise completely fine. No significant oil consumption
> either.
>
> The dealer here in Thailand suggests to open up the engine, and
> perhaps change the hydraulic lifter, but he is basically not really
> sure, what causes the problem.
>
> I have used a Fuel Injector Cleaner without success.
>
> Most likely, it is not the piston slap problem, as the car is built in
> 1999.
> If it is the lifter, why stopping and restarting the engine clears the
> noise
> immediately sometimes, but not all the time.
> The noise appears at a cold engine and on a warm engine as well, and
> during idle but during normal driving conditions as well, but
> randomly, it seems. If drive at high rpm, there is generally no noise.
>
> What could cause that noise?
>
> Any help from you old timers and experts would be greatly appreciated.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Could the cause of this problem be found
within the electronic / contact / sensor input complex?

Today, no noise at all, so far. No noise at cold start,
no noise during normal driving conditions with a warm
engine. No noise whatsoever.

So, if it would be a purely mechanical problem such as
piston slap, hydraulic lifters, or carbon build up, why is
there no noise today?

I am living in the tropics (Thailand) with a very high humidity
of around 80-90%. Could it be, that somewhere, an electronic
contact or a wrong sensor input causes the engine to produce
this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Could the cause of this problem be found
within the electronic / contact / sensor input complex?

Today, no noise at all, so far. No noise at cold start,
no noise during normal driving conditions with a warm
engine. No noise whatsoever.

So, if it would be a purely mechanical problem such as
piston slap, hydraulic lifters, or carbon build up, why is
there no noise today?

I am living in the tropics (Thailand) with a very high humidity
of around 80-90%. Could it be, that somewhere, an electronic
contact or a wrong sensor input causes the engine to produce
this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Could the cause of this problem be found
within the electronic / contact / sensor input complex?

Today, no noise at all, so far. No noise at cold start,
no noise during normal driving conditions with a warm
engine. No noise whatsoever.

So, if it would be a purely mechanical problem such as
piston slap, hydraulic lifters, or carbon build up, why is
there no noise today?

I am living in the tropics (Thailand) with a very high humidity
of around 80-90%. Could it be, that somewhere, an electronic
contact or a wrong sensor input causes the engine to produce
this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Hydraulic lifters can make an intermittent noise such as you describe. This
is because the source of the noise is a lifter that has not been filled with
oil. This is usually caused by a bad seal or a blockage, but sometimes they
pump down over night; sometimes not. Back in previous decades when these
things were a relatively new design they would act up when the vehicle
needed an oil change. After an oil change, all would be quiet again. Now
they are thought to be better designed, but you still get one acting up now
and then.

Humidity where you live could contribute to oil contamination and lifter
failure, but since you change your oil fairly often (manufacturers recommend
7,000 miles) I do not suspect this as the cause.

Earle

"Robert Goldpalm" <goldpalm@loxinfo.co.th> wrote in message
news:68468edd.0311092202.7eff882d@posting.google.c om...
> Could the cause of this problem be found
> within the electronic / contact / sensor input complex?
>
> Today, no noise at all, so far. No noise at cold start,
> no noise during normal driving conditions with a warm
> engine. No noise whatsoever.
>
> So, if it would be a purely mechanical problem such as
> piston slap, hydraulic lifters, or carbon build up, why is
> there no noise today?
>
> I am living in the tropics (Thailand) with a very high humidity
> of around 80-90%. Could it be, that somewhere, an electronic
> contact or a wrong sensor input causes the engine to produce
> this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Hydraulic lifters can make an intermittent noise such as you describe. This
is because the source of the noise is a lifter that has not been filled with
oil. This is usually caused by a bad seal or a blockage, but sometimes they
pump down over night; sometimes not. Back in previous decades when these
things were a relatively new design they would act up when the vehicle
needed an oil change. After an oil change, all would be quiet again. Now
they are thought to be better designed, but you still get one acting up now
and then.

Humidity where you live could contribute to oil contamination and lifter
failure, but since you change your oil fairly often (manufacturers recommend
7,000 miles) I do not suspect this as the cause.

Earle

"Robert Goldpalm" <goldpalm@loxinfo.co.th> wrote in message
news:68468edd.0311092202.7eff882d@posting.google.c om...
> Could the cause of this problem be found
> within the electronic / contact / sensor input complex?
>
> Today, no noise at all, so far. No noise at cold start,
> no noise during normal driving conditions with a warm
> engine. No noise whatsoever.
>
> So, if it would be a purely mechanical problem such as
> piston slap, hydraulic lifters, or carbon build up, why is
> there no noise today?
>
> I am living in the tropics (Thailand) with a very high humidity
> of around 80-90%. Could it be, that somewhere, an electronic
> contact or a wrong sensor input causes the engine to produce
> this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Hydraulic lifters can make an intermittent noise such as you describe. This
is because the source of the noise is a lifter that has not been filled with
oil. This is usually caused by a bad seal or a blockage, but sometimes they
pump down over night; sometimes not. Back in previous decades when these
things were a relatively new design they would act up when the vehicle
needed an oil change. After an oil change, all would be quiet again. Now
they are thought to be better designed, but you still get one acting up now
and then.

Humidity where you live could contribute to oil contamination and lifter
failure, but since you change your oil fairly often (manufacturers recommend
7,000 miles) I do not suspect this as the cause.

Earle

"Robert Goldpalm" <goldpalm@loxinfo.co.th> wrote in message
news:68468edd.0311092202.7eff882d@posting.google.c om...
> Could the cause of this problem be found
> within the electronic / contact / sensor input complex?
>
> Today, no noise at all, so far. No noise at cold start,
> no noise during normal driving conditions with a warm
> engine. No noise whatsoever.
>
> So, if it would be a purely mechanical problem such as
> piston slap, hydraulic lifters, or carbon build up, why is
> there no noise today?
>
> I am living in the tropics (Thailand) with a very high humidity
> of around 80-90%. Could it be, that somewhere, an electronic
> contact or a wrong sensor input causes the engine to produce
> this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Did you check your fan clutch?

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> Could the cause of this problem be found
> within the electronic / contact / sensor input complex?
>
> Today, no noise at all, so far. No noise at cold start,
> no noise during normal driving conditions with a warm
> engine. No noise whatsoever.
>
> So, if it would be a purely mechanical problem such as
> piston slap, hydraulic lifters, or carbon build up, why is
> there no noise today?
>
> I am living in the tropics (Thailand) with a very high humidity
> of around 80-90%. Could it be, that somewhere, an electronic
> contact or a wrong sensor input causes the engine to produce
> this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Did you check your fan clutch?

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> Could the cause of this problem be found
> within the electronic / contact / sensor input complex?
>
> Today, no noise at all, so far. No noise at cold start,
> no noise during normal driving conditions with a warm
> engine. No noise whatsoever.
>
> So, if it would be a purely mechanical problem such as
> piston slap, hydraulic lifters, or carbon build up, why is
> there no noise today?
>
> I am living in the tropics (Thailand) with a very high humidity
> of around 80-90%. Could it be, that somewhere, an electronic
> contact or a wrong sensor input causes the engine to produce
> this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Did you check your fan clutch?

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> Could the cause of this problem be found
> within the electronic / contact / sensor input complex?
>
> Today, no noise at all, so far. No noise at cold start,
> no noise during normal driving conditions with a warm
> engine. No noise whatsoever.
>
> So, if it would be a purely mechanical problem such as
> piston slap, hydraulic lifters, or carbon build up, why is
> there no noise today?
>
> I am living in the tropics (Thailand) with a very high humidity
> of around 80-90%. Could it be, that somewhere, an electronic
> contact or a wrong sensor input causes the engine to produce
> this ticking / knocking sounds sometimes?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

>
> Robert Goldpalm wrote:
>>
>> Could the cause of this problem be found
>> within the electronic / contact / sensor input complex?
>>
>> Today, no noise at all, so far. No noise at cold start,
>> no noise during normal driving conditions with a warm
>> engine. No noise whatsoever.
>>
>> So, if it would be a purely mechanical problem such as
>> piston slap, hydraulic lifters, or carbon build up, why is
>> there no noise today?
>>
>> I am living in the tropics (Thailand) with a very high humidity
>> of around 80-90%. Could it be, that somewhere, an electronic
>> contact or a wrong sensor input causes the engine to produce
>> this ticking / knocking sounds sometimes?

Approximately 11/10/03 09:04, Mike Romain uttered for posterity:

> Did you check your fan clutch?

Does the vibration damper on the 4.0 get loose and sound
pretty close to a piston knock? Have had it happen on
other engines, dunno if the 4.0 unit can do it. Actually
on the other engine it wasn't loose, it had a big crack
in it that made the most noise when cold.

--
My governor can kick your governor's ass

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

>
> Robert Goldpalm wrote:
>>
>> Could the cause of this problem be found
>> within the electronic / contact / sensor input complex?
>>
>> Today, no noise at all, so far. No noise at cold start,
>> no noise during normal driving conditions with a warm
>> engine. No noise whatsoever.
>>
>> So, if it would be a purely mechanical problem such as
>> piston slap, hydraulic lifters, or carbon build up, why is
>> there no noise today?
>>
>> I am living in the tropics (Thailand) with a very high humidity
>> of around 80-90%. Could it be, that somewhere, an electronic
>> contact or a wrong sensor input causes the engine to produce
>> this ticking / knocking sounds sometimes?

Approximately 11/10/03 09:04, Mike Romain uttered for posterity:

> Did you check your fan clutch?

Does the vibration damper on the 4.0 get loose and sound
pretty close to a piston knock? Have had it happen on
other engines, dunno if the 4.0 unit can do it. Actually
on the other engine it wasn't loose, it had a big crack
in it that made the most noise when cold.

--
My governor can kick your governor's ass

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

>
> Robert Goldpalm wrote:
>>
>> Could the cause of this problem be found
>> within the electronic / contact / sensor input complex?
>>
>> Today, no noise at all, so far. No noise at cold start,
>> no noise during normal driving conditions with a warm
>> engine. No noise whatsoever.
>>
>> So, if it would be a purely mechanical problem such as
>> piston slap, hydraulic lifters, or carbon build up, why is
>> there no noise today?
>>
>> I am living in the tropics (Thailand) with a very high humidity
>> of around 80-90%. Could it be, that somewhere, an electronic
>> contact or a wrong sensor input causes the engine to produce
>> this ticking / knocking sounds sometimes?

Approximately 11/10/03 09:04, Mike Romain uttered for posterity:

> Did you check your fan clutch?

Does the vibration damper on the 4.0 get loose and sound
pretty close to a piston knock? Have had it happen on
other engines, dunno if the 4.0 unit can do it. Actually
on the other engine it wasn't loose, it had a big crack
in it that made the most noise when cold.

--
My governor can kick your governor's ass

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Lon Stowell wrote:
>
> >
> > Robert Goldpalm wrote:
> >>
> >> Could the cause of this problem be found
> >> within the electronic / contact / sensor input complex?
> >>
> >> Today, no noise at all, so far. No noise at cold start,
> >> no noise during normal driving conditions with a warm
> >> engine. No noise whatsoever.
> >>
> >> So, if it would be a purely mechanical problem such as
> >> piston slap, hydraulic lifters, or carbon build up, why is
> >> there no noise today?
> >>
> >> I am living in the tropics (Thailand) with a very high humidity
> >> of around 80-90%. Could it be, that somewhere, an electronic
> >> contact or a wrong sensor input causes the engine to produce
> >> this ticking / knocking sounds sometimes?
>
> Approximately 11/10/03 09:04, Mike Romain uttered for posterity:
>
> > Did you check your fan clutch?
>
> Does the vibration damper on the 4.0 get loose and sound
> pretty close to a piston knock? Have had it happen on
> other engines, dunno if the 4.0 unit can do it. Actually
> on the other engine it wasn't loose, it had a big crack
> in it that made the most noise when cold.
>
> --

Yes, it can go bad, but usually it starts eating the fan belt before it
knocks from what I have read.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Lon Stowell wrote:
>
> >
> > Robert Goldpalm wrote:
> >>
> >> Could the cause of this problem be found
> >> within the electronic / contact / sensor input complex?
> >>
> >> Today, no noise at all, so far. No noise at cold start,
> >> no noise during normal driving conditions with a warm
> >> engine. No noise whatsoever.
> >>
> >> So, if it would be a purely mechanical problem such as
> >> piston slap, hydraulic lifters, or carbon build up, why is
> >> there no noise today?
> >>
> >> I am living in the tropics (Thailand) with a very high humidity
> >> of around 80-90%. Could it be, that somewhere, an electronic
> >> contact or a wrong sensor input causes the engine to produce
> >> this ticking / knocking sounds sometimes?
>
> Approximately 11/10/03 09:04, Mike Romain uttered for posterity:
>
> > Did you check your fan clutch?
>
> Does the vibration damper on the 4.0 get loose and sound
> pretty close to a piston knock? Have had it happen on
> other engines, dunno if the 4.0 unit can do it. Actually
> on the other engine it wasn't loose, it had a big crack
> in it that made the most noise when cold.
>
> --

Yes, it can go bad, but usually it starts eating the fan belt before it
knocks from what I have read.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Lon Stowell wrote:
>
> >
> > Robert Goldpalm wrote:
> >>
> >> Could the cause of this problem be found
> >> within the electronic / contact / sensor input complex?
> >>
> >> Today, no noise at all, so far. No noise at cold start,
> >> no noise during normal driving conditions with a warm
> >> engine. No noise whatsoever.
> >>
> >> So, if it would be a purely mechanical problem such as
> >> piston slap, hydraulic lifters, or carbon build up, why is
> >> there no noise today?
> >>
> >> I am living in the tropics (Thailand) with a very high humidity
> >> of around 80-90%. Could it be, that somewhere, an electronic
> >> contact or a wrong sensor input causes the engine to produce
> >> this ticking / knocking sounds sometimes?
>
> Approximately 11/10/03 09:04, Mike Romain uttered for posterity:
>
> > Did you check your fan clutch?
>
> Does the vibration damper on the 4.0 get loose and sound
> pretty close to a piston knock? Have had it happen on
> other engines, dunno if the 4.0 unit can do it. Actually
> on the other engine it wasn't loose, it had a big crack
> in it that made the most noise when cold.
>
> --

Yes, it can go bad, but usually it starts eating the fan belt before it
knocks from what I have read.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Mike Romain did pass the time by typing:
> Lon Stowell wrote:
>>
>>>
>>> Robert Goldpalm wrote:

---8<---

>>> Did you check your fan clutch?
>>
>> Does the vibration damper on the 4.0 get loose and sound
>> pretty close to a piston knock? Have had it happen on
>> other engines, dunno if the 4.0 unit can do it. Actually
>> on the other engine it wasn't loose, it had a big crack
>> in it that made the most noise when cold.

> Yes, it can go bad, but usually it starts eating the fan belt before it
> knocks from what I have read.

That's my understanding also.

A mechanic down in Biloxi told me this trick. YMMV
Take a feel of the rubber spacer in the vibration damper,
if it's sticking out or the surfaces aren't even then it is
starting to turn loose.

He also mentioned running a razor blade around the face and checking
to see if any rubber comes off. Although I just go by feel.

I still think taking a mechanics stethoscope to the engine is the best bet.

--
DougW

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Mike Romain did pass the time by typing:
> Lon Stowell wrote:
>>
>>>
>>> Robert Goldpalm wrote:

---8<---

>>> Did you check your fan clutch?
>>
>> Does the vibration damper on the 4.0 get loose and sound
>> pretty close to a piston knock? Have had it happen on
>> other engines, dunno if the 4.0 unit can do it. Actually
>> on the other engine it wasn't loose, it had a big crack
>> in it that made the most noise when cold.

> Yes, it can go bad, but usually it starts eating the fan belt before it
> knocks from what I have read.

That's my understanding also.

A mechanic down in Biloxi told me this trick. YMMV
Take a feel of the rubber spacer in the vibration damper,
if it's sticking out or the surfaces aren't even then it is
starting to turn loose.

He also mentioned running a razor blade around the face and checking
to see if any rubber comes off. Although I just go by feel.

I still think taking a mechanics stethoscope to the engine is the best bet.

--
DougW

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Mike Romain did pass the time by typing:
> Lon Stowell wrote:
>>
>>>
>>> Robert Goldpalm wrote:

---8<---

>>> Did you check your fan clutch?
>>
>> Does the vibration damper on the 4.0 get loose and sound
>> pretty close to a piston knock? Have had it happen on
>> other engines, dunno if the 4.0 unit can do it. Actually
>> on the other engine it wasn't loose, it had a big crack
>> in it that made the most noise when cold.

> Yes, it can go bad, but usually it starts eating the fan belt before it
> knocks from what I have read.

That's my understanding also.

A mechanic down in Biloxi told me this trick. YMMV
Take a feel of the rubber spacer in the vibration damper,
if it's sticking out or the surfaces aren't even then it is
starting to turn loose.

He also mentioned running a razor blade around the face and checking
to see if any rubber comes off. Although I just go by feel.

I still think taking a mechanics stethoscope to the engine is the best bet.

--
DougW

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

On Mon, 10 Nov 2003 18:19:23 UTC Mike Romain <romainm@sympatico.ca>
wrote:

> Lon Stowell wrote:
> >
> > >
> > > Robert Goldpalm wrote:
> > >>
> > >> Could the cause of this problem be found
> > >> within the electronic / contact / sensor input complex?
> > >>
> > >> Today, no noise at all, so far. No noise at cold start,
> > >> no noise during normal driving conditions with a warm
> > >> engine. No noise whatsoever.
> > >>
> > >> So, if it would be a purely mechanical problem such as
> > >> piston slap, hydraulic lifters, or carbon build up, why is
> > >> there no noise today?
> > >>
> > >> I am living in the tropics (Thailand) with a very high humidity
> > >> of around 80-90%. Could it be, that somewhere, an electronic
> > >> contact or a wrong sensor input causes the engine to produce
> > >> this ticking / knocking sounds sometimes?
> >
> > Approximately 11/10/03 09:04, Mike Romain uttered for posterity:
> >
> > > Did you check your fan clutch?
> >
> > Does the vibration damper on the 4.0 get loose and sound
> > pretty close to a piston knock? Have had it happen on
> > other engines, dunno if the 4.0 unit can do it. Actually
> > on the other engine it wasn't loose, it had a big crack
> > in it that made the most noise when cold.
> >
> > --
>
> Yes, it can go bad, but usually it starts eating the fan belt before it
> knocks from what I have read.

First hand observation: right on. If it's gotten to the point of
being loose enough to knock you're probably too poor from replacing
belts to do anything about it.

A worn out water pump will also do this - but not for long. The other
culprit is the power steering pump and that can go on for a while
since the big impeller just whops the case. All of these thing
produce more of a thumb than a hard knock, tho.

I think your suggestion of a stethascope is the best one - localize
the noise then let us all guess.

--
Will Honea <whonea@codenet.net>

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

On Mon, 10 Nov 2003 18:19:23 UTC Mike Romain <romainm@sympatico.ca>
wrote:

> Lon Stowell wrote:
> >
> > >
> > > Robert Goldpalm wrote:
> > >>
> > >> Could the cause of this problem be found
> > >> within the electronic / contact / sensor input complex?
> > >>
> > >> Today, no noise at all, so far. No noise at cold start,
> > >> no noise during normal driving conditions with a warm
> > >> engine. No noise whatsoever.
> > >>
> > >> So, if it would be a purely mechanical problem such as
> > >> piston slap, hydraulic lifters, or carbon build up, why is
> > >> there no noise today?
> > >>
> > >> I am living in the tropics (Thailand) with a very high humidity
> > >> of around 80-90%. Could it be, that somewhere, an electronic
> > >> contact or a wrong sensor input causes the engine to produce
> > >> this ticking / knocking sounds sometimes?
> >
> > Approximately 11/10/03 09:04, Mike Romain uttered for posterity:
> >
> > > Did you check your fan clutch?
> >
> > Does the vibration damper on the 4.0 get loose and sound
> > pretty close to a piston knock? Have had it happen on
> > other engines, dunno if the 4.0 unit can do it. Actually
> > on the other engine it wasn't loose, it had a big crack
> > in it that made the most noise when cold.
> >
> > --
>
> Yes, it can go bad, but usually it starts eating the fan belt before it
> knocks from what I have read.

First hand observation: right on. If it's gotten to the point of
being loose enough to knock you're probably too poor from replacing
belts to do anything about it.

A worn out water pump will also do this - but not for long. The other
culprit is the power steering pump and that can go on for a while
since the big impeller just whops the case. All of these thing
produce more of a thumb than a hard knock, tho.

I think your suggestion of a stethascope is the best one - localize
the noise then let us all guess.

--
Will Honea <whonea@codenet.net>

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

On Mon, 10 Nov 2003 18:19:23 UTC Mike Romain <romainm@sympatico.ca>
wrote:

> Lon Stowell wrote:
> >
> > >
> > > Robert Goldpalm wrote:
> > >>
> > >> Could the cause of this problem be found
> > >> within the electronic / contact / sensor input complex?
> > >>
> > >> Today, no noise at all, so far. No noise at cold start,
> > >> no noise during normal driving conditions with a warm
> > >> engine. No noise whatsoever.
> > >>
> > >> So, if it would be a purely mechanical problem such as
> > >> piston slap, hydraulic lifters, or carbon build up, why is
> > >> there no noise today?
> > >>
> > >> I am living in the tropics (Thailand) with a very high humidity
> > >> of around 80-90%. Could it be, that somewhere, an electronic
> > >> contact or a wrong sensor input causes the engine to produce
> > >> this ticking / knocking sounds sometimes?
> >
> > Approximately 11/10/03 09:04, Mike Romain uttered for posterity:
> >
> > > Did you check your fan clutch?
> >
> > Does the vibration damper on the 4.0 get loose and sound
> > pretty close to a piston knock? Have had it happen on
> > other engines, dunno if the 4.0 unit can do it. Actually
> > on the other engine it wasn't loose, it had a big crack
> > in it that made the most noise when cold.
> >
> > --
>
> Yes, it can go bad, but usually it starts eating the fan belt before it
> knocks from what I have read.

First hand observation: right on. If it's gotten to the point of
being loose enough to knock you're probably too poor from replacing
belts to do anything about it.

A worn out water pump will also do this - but not for long. The other
culprit is the power steering pump and that can go on for a while
since the big impeller just whops the case. All of these thing
produce more of a thumb than a hard knock, tho.

I think your suggestion of a stethascope is the best one - localize
the noise then let us all guess.

--
Will Honea <whonea@codenet.net>

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Thanks for all the input so far.

Checking around with an improvised stethoscope, the noise seems to
come
from the engine close to cylinder ( 6 ?) , close to the place, where
the
PCV is located.

Take today's history for example. Started the cold (it's the tropics)
engine. No noise at all. Went to the local mall about 3 miles away,
and
no noise during the drive there. While slowly cruising at about 1,500
rpm through the parking area, the noise (more like a knocking, not a
ticking) appeared.
During idle, the knocking was still there, then stopped. With the car
parked, raving the engine up to about 1,500 to 2000 rpm and letting it
slow down to idle again, the symptoms came back during idle for about
30 Seconds to a minute, then stopped.

I decided to drive strait to the dealer who is only away another few
miles. On
the way there, no noise at all. At the dealer, only a very slight
ticking sound, but no knocking.

Every time I am at the dealer, there is only a ticking, but never a
strong knocking.
When this metallic knocking sound appears, you can hear it very
clearly, even quit far away from the car.

From reading through similar messages, I would say, it sounds perhaps
like the
"Piston Slap", but since I have a '99 model, this particular problem
should not
apply to my engine I guess.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Thanks for all the input so far.

Checking around with an improvised stethoscope, the noise seems to
come
from the engine close to cylinder ( 6 ?) , close to the place, where
the
PCV is located.

Take today's history for example. Started the cold (it's the tropics)
engine. No noise at all. Went to the local mall about 3 miles away,
and
no noise during the drive there. While slowly cruising at about 1,500
rpm through the parking area, the noise (more like a knocking, not a
ticking) appeared.
During idle, the knocking was still there, then stopped. With the car
parked, raving the engine up to about 1,500 to 2000 rpm and letting it
slow down to idle again, the symptoms came back during idle for about
30 Seconds to a minute, then stopped.

I decided to drive strait to the dealer who is only away another few
miles. On
the way there, no noise at all. At the dealer, only a very slight
ticking sound, but no knocking.

Every time I am at the dealer, there is only a ticking, but never a
strong knocking.
When this metallic knocking sound appears, you can hear it very
clearly, even quit far away from the car.

From reading through similar messages, I would say, it sounds perhaps
like the
"Piston Slap", but since I have a '99 model, this particular problem
should not
apply to my engine I guess.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Thanks for all the input so far.

Checking around with an improvised stethoscope, the noise seems to
come
from the engine close to cylinder ( 6 ?) , close to the place, where
the
PCV is located.

Take today's history for example. Started the cold (it's the tropics)
engine. No noise at all. Went to the local mall about 3 miles away,
and
no noise during the drive there. While slowly cruising at about 1,500
rpm through the parking area, the noise (more like a knocking, not a
ticking) appeared.
During idle, the knocking was still there, then stopped. With the car
parked, raving the engine up to about 1,500 to 2000 rpm and letting it
slow down to idle again, the symptoms came back during idle for about
30 Seconds to a minute, then stopped.

I decided to drive strait to the dealer who is only away another few
miles. On
the way there, no noise at all. At the dealer, only a very slight
ticking sound, but no knocking.

Every time I am at the dealer, there is only a ticking, but never a
strong knocking.
When this metallic knocking sound appears, you can hear it very
clearly, even quit far away from the car.

From reading through similar messages, I would say, it sounds perhaps
like the
"Piston Slap", but since I have a '99 model, this particular problem
should not
apply to my engine I guess.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Exhaust pipe hitting on something is my next guess.

Or the heat shield on the cat is loose.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> Thanks for all the input so far.
>
> Checking around with an improvised stethoscope, the noise seems to
> come
> from the engine close to cylinder ( 6 ?) , close to the place, where
> the
> PCV is located.
>
> Take today's history for example. Started the cold (it's the tropics)
> engine. No noise at all. Went to the local mall about 3 miles away,
> and
> no noise during the drive there. While slowly cruising at about 1,500
> rpm through the parking area, the noise (more like a knocking, not a
> ticking) appeared.
> During idle, the knocking was still there, then stopped. With the car
> parked, raving the engine up to about 1,500 to 2000 rpm and letting it
> slow down to idle again, the symptoms came back during idle for about
> 30 Seconds to a minute, then stopped.
>
> I decided to drive strait to the dealer who is only away another few
> miles. On
> the way there, no noise at all. At the dealer, only a very slight
> ticking sound, but no knocking.
>
> Every time I am at the dealer, there is only a ticking, but never a
> strong knocking.
> When this metallic knocking sound appears, you can hear it very
> clearly, even quit far away from the car.
>
> From reading through similar messages, I would say, it sounds perhaps
> like the
> "Piston Slap", but since I have a '99 model, this particular problem
> should not
> apply to my engine I guess.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Exhaust pipe hitting on something is my next guess.

Or the heat shield on the cat is loose.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> Thanks for all the input so far.
>
> Checking around with an improvised stethoscope, the noise seems to
> come
> from the engine close to cylinder ( 6 ?) , close to the place, where
> the
> PCV is located.
>
> Take today's history for example. Started the cold (it's the tropics)
> engine. No noise at all. Went to the local mall about 3 miles away,
> and
> no noise during the drive there. While slowly cruising at about 1,500
> rpm through the parking area, the noise (more like a knocking, not a
> ticking) appeared.
> During idle, the knocking was still there, then stopped. With the car
> parked, raving the engine up to about 1,500 to 2000 rpm and letting it
> slow down to idle again, the symptoms came back during idle for about
> 30 Seconds to a minute, then stopped.
>
> I decided to drive strait to the dealer who is only away another few
> miles. On
> the way there, no noise at all. At the dealer, only a very slight
> ticking sound, but no knocking.
>
> Every time I am at the dealer, there is only a ticking, but never a
> strong knocking.
> When this metallic knocking sound appears, you can hear it very
> clearly, even quit far away from the car.
>
> From reading through similar messages, I would say, it sounds perhaps
> like the
> "Piston Slap", but since I have a '99 model, this particular problem
> should not
> apply to my engine I guess.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Exhaust pipe hitting on something is my next guess.

Or the heat shield on the cat is loose.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Robert Goldpalm wrote:
>
> Thanks for all the input so far.
>
> Checking around with an improvised stethoscope, the noise seems to
> come
> from the engine close to cylinder ( 6 ?) , close to the place, where
> the
> PCV is located.
>
> Take today's history for example. Started the cold (it's the tropics)
> engine. No noise at all. Went to the local mall about 3 miles away,
> and
> no noise during the drive there. While slowly cruising at about 1,500
> rpm through the parking area, the noise (more like a knocking, not a
> ticking) appeared.
> During idle, the knocking was still there, then stopped. With the car
> parked, raving the engine up to about 1,500 to 2000 rpm and letting it
> slow down to idle again, the symptoms came back during idle for about
> 30 Seconds to a minute, then stopped.
>
> I decided to drive strait to the dealer who is only away another few
> miles. On
> the way there, no noise at all. At the dealer, only a very slight
> ticking sound, but no knocking.
>
> Every time I am at the dealer, there is only a ticking, but never a
> strong knocking.
> When this metallic knocking sound appears, you can hear it very
> clearly, even quit far away from the car.
>
> From reading through similar messages, I would say, it sounds perhaps
> like the
> "Piston Slap", but since I have a '99 model, this particular problem
> should not
> apply to my engine I guess.

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Now it's beginning to sound like a bad lifter letting the pushrod get
slack in it - notice any roughnes in the engine when it's banging
away? Given a little bleed down, the extra spacing will produce a
pretty good noise when the pushrod has any substantial air gap between
it and the rocker arm. Another oil change might clean this up or
trying one change with a heavier weight oil - like going from 10-30 to
20-40 - might make a difference.

On Tue, 11 Nov 2003 05:39:52 UTC goldpalm@loxinfo.co.th (Robert
Goldpalm) wrote:

> Thanks for all the input so far.
>
> Checking around with an improvised stethoscope, the noise seems to
> come
> from the engine close to cylinder ( 6 ?) , close to the place, where
> the
> PCV is located.
>
> Take today's history for example. Started the cold (it's the tropics)
> engine. No noise at all. Went to the local mall about 3 miles away,
> and
> no noise during the drive there. While slowly cruising at about 1,500
> rpm through the parking area, the noise (more like a knocking, not a
> ticking) appeared.
> During idle, the knocking was still there, then stopped. With the car
> parked, raving the engine up to about 1,500 to 2000 rpm and letting it
> slow down to idle again, the symptoms came back during idle for about
> 30 Seconds to a minute, then stopped.
>
> I decided to drive strait to the dealer who is only away another few
> miles. On
> the way there, no noise at all. At the dealer, only a very slight
> ticking sound, but no knocking.
>
> Every time I am at the dealer, there is only a ticking, but never a
> strong knocking.
> When this metallic knocking sound appears, you can hear it very
> clearly, even quit far away from the car.
>
> From reading through similar messages, I would say, it sounds perhaps
> like the
> "Piston Slap", but since I have a '99 model, this particular problem
> should not
> apply to my engine I guess.


--
Will Honea <whonea@codenet.net>

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Now it's beginning to sound like a bad lifter letting the pushrod get
slack in it - notice any roughnes in the engine when it's banging
away? Given a little bleed down, the extra spacing will produce a
pretty good noise when the pushrod has any substantial air gap between
it and the rocker arm. Another oil change might clean this up or
trying one change with a heavier weight oil - like going from 10-30 to
20-40 - might make a difference.

On Tue, 11 Nov 2003 05:39:52 UTC goldpalm@loxinfo.co.th (Robert
Goldpalm) wrote:

> Thanks for all the input so far.
>
> Checking around with an improvised stethoscope, the noise seems to
> come
> from the engine close to cylinder ( 6 ?) , close to the place, where
> the
> PCV is located.
>
> Take today's history for example. Started the cold (it's the tropics)
> engine. No noise at all. Went to the local mall about 3 miles away,
> and
> no noise during the drive there. While slowly cruising at about 1,500
> rpm through the parking area, the noise (more like a knocking, not a
> ticking) appeared.
> During idle, the knocking was still there, then stopped. With the car
> parked, raving the engine up to about 1,500 to 2000 rpm and letting it
> slow down to idle again, the symptoms came back during idle for about
> 30 Seconds to a minute, then stopped.
>
> I decided to drive strait to the dealer who is only away another few
> miles. On
> the way there, no noise at all. At the dealer, only a very slight
> ticking sound, but no knocking.
>
> Every time I am at the dealer, there is only a ticking, but never a
> strong knocking.
> When this metallic knocking sound appears, you can hear it very
> clearly, even quit far away from the car.
>
> From reading through similar messages, I would say, it sounds perhaps
> like the
> "Piston Slap", but since I have a '99 model, this particular problem
> should not
> apply to my engine I guess.


--
Will Honea <whonea@codenet.net>

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Now it's beginning to sound like a bad lifter letting the pushrod get
slack in it - notice any roughnes in the engine when it's banging
away? Given a little bleed down, the extra spacing will produce a
pretty good noise when the pushrod has any substantial air gap between
it and the rocker arm. Another oil change might clean this up or
trying one change with a heavier weight oil - like going from 10-30 to
20-40 - might make a difference.

On Tue, 11 Nov 2003 05:39:52 UTC goldpalm@loxinfo.co.th (Robert
Goldpalm) wrote:

> Thanks for all the input so far.
>
> Checking around with an improvised stethoscope, the noise seems to
> come
> from the engine close to cylinder ( 6 ?) , close to the place, where
> the
> PCV is located.
>
> Take today's history for example. Started the cold (it's the tropics)
> engine. No noise at all. Went to the local mall about 3 miles away,
> and
> no noise during the drive there. While slowly cruising at about 1,500
> rpm through the parking area, the noise (more like a knocking, not a
> ticking) appeared.
> During idle, the knocking was still there, then stopped. With the car
> parked, raving the engine up to about 1,500 to 2000 rpm and letting it
> slow down to idle again, the symptoms came back during idle for about
> 30 Seconds to a minute, then stopped.
>
> I decided to drive strait to the dealer who is only away another few
> miles. On
> the way there, no noise at all. At the dealer, only a very slight
> ticking sound, but no knocking.
>
> Every time I am at the dealer, there is only a ticking, but never a
> strong knocking.
> When this metallic knocking sound appears, you can hear it very
> clearly, even quit far away from the car.
>
> From reading through similar messages, I would say, it sounds perhaps
> like the
> "Piston Slap", but since I have a '99 model, this particular problem
> should not
> apply to my engine I guess.


--
Will Honea <whonea@codenet.net>

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Thanks again for all the suggestions.

So far, I have now:

-Drained about one quarter of oil, refilled
with ATF and driven the car about 100 miles.

-Made a complete oil & filter (Mopar) change to Valvoline Maxlife
10W-40, a heavier weight oil as suggested here.

-This is the second day now with a 10W-40 oil fill, and this
morning, the engine has made again this distinct noise at
cold (82 F) start. The noise did not go away for a few minutes,
then resided from a loud metallic tick to a softer, more subdued
ticking sound that could be still heard most of the time during
driving.

-To accurately describe the sound is not so easy, but I would
say, it is similar to a smaller direct injected diesel engine,
comming from cylinder 6 or 5.

Does that sound like a lifter noise? If yes, what are the prospects?
Can the engine deteriorate more, or is it just an annoyance, one has to get used to?

The dealer where the car was purchased, switched from Chrysler
to Land Rover recently, and Jeeps are serviced now by the local Mercedes
dealer. There, they have only one mechanic who is responsible for
Jeeps, and he admitted, that he actually has never opened a 4.0 L/6
engine before.
Now, unlucky me, if the engine really needs replacement lifters,
that guy will somehow experiment with my engine for the first time.
I can also not sell the car because of the noise it makes. I could just
drive until something gives, and that would be it, but perhaps it would
be a long way from now.

So, what do you think?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Thanks again for all the suggestions.

So far, I have now:

-Drained about one quarter of oil, refilled
with ATF and driven the car about 100 miles.

-Made a complete oil & filter (Mopar) change to Valvoline Maxlife
10W-40, a heavier weight oil as suggested here.

-This is the second day now with a 10W-40 oil fill, and this
morning, the engine has made again this distinct noise at
cold (82 F) start. The noise did not go away for a few minutes,
then resided from a loud metallic tick to a softer, more subdued
ticking sound that could be still heard most of the time during
driving.

-To accurately describe the sound is not so easy, but I would
say, it is similar to a smaller direct injected diesel engine,
comming from cylinder 6 or 5.

Does that sound like a lifter noise? If yes, what are the prospects?
Can the engine deteriorate more, or is it just an annoyance, one has to get used to?

The dealer where the car was purchased, switched from Chrysler
to Land Rover recently, and Jeeps are serviced now by the local Mercedes
dealer. There, they have only one mechanic who is responsible for
Jeeps, and he admitted, that he actually has never opened a 4.0 L/6
engine before.
Now, unlucky me, if the engine really needs replacement lifters,
that guy will somehow experiment with my engine for the first time.
I can also not sell the car because of the noise it makes. I could just
drive until something gives, and that would be it, but perhaps it would
be a long way from now.

So, what do you think?

Re: Hammering / knocking noise on 4.0L6 '99 Cherokee
 

Thanks again for all the suggestions.

So far, I have now:

-Drained about one quarter of oil, refilled
with ATF and driven the car about 100 miles.

-Made a complete oil & filter (Mopar) change to Valvoline Maxlife
10W-40, a heavier weight oil as suggested here.

-This is the second day now with a 10W-40 oil fill, and this
morning, the engine has made again this distinct noise at
cold (82 F) start. The noise did not go away for a few minutes,
then resided from a loud metallic tick to a softer, more subdued
ticking sound that could be still heard most of the time during
driving.

-To accurately describe the sound is not so easy, but I would
say, it is similar to a smaller direct injected diesel engine,
comming from cylinder 6 or 5.

Does that sound like a lifter noise? If yes, what are the prospects?
Can the engine deteriorate more, or is it just an annoyance, one has to get used to?

The dealer where the car was purchased, switched from Chrysler
to Land Rover recently, and Jeeps are serviced now by the local Mercedes
dealer. There, they have only one mechanic who is responsible for
Jeeps, and he admitted, that he actually has never opened a 4.0 L/6
engine before.
Now, unlucky me, if the engine really needs replacement lifters,
that guy will somehow experiment with my engine for the first time.
I can also not sell the car because of the noise it makes. I could just
drive until something gives, and that would be it, but perhaps it would
be a long way from now.

So, what do you think?