Engine knock on 93 xj 4.0
 

Hi all, I Wish everyone a merry christmas and a happy new year!

I have a 93 xj with a 4.0 with a 116,000 miles on it and runs great good oil
pressure, no oil leaks and the engine burns about a quart of oil between
changes and has had regular oil changes every 3-4k and engine is clean. My
Question is after it warms up a bit there is a rattle or knock coming from
the bottom end and the oil pressure stays above 40 psi at above 1500 rpm and
about 30 at idle other wise the top end seems quiet and with no passed calif
emissions with no problems.I was wondering if I should be concerned or not I
don't want to throw a rod on the road some day. I have heard other 4.0 and
some seem Quiet and others have this knock without problems. I heard that
there maybe some years of 4.0 with a problem with piston slap. Should I be
worried or not this is my daily driver and with some minor off roading when
going camping. I know some people that got more than 300,000 miles out of
these engines!

Any suggestions or comments will be helpful Thanks.

Re: Engine knock on 93 xj 4.0
 

Knocks are really deceiving....

I like to use an automotive stethoscope to help try to nail them down.

I usually associate low oil pressure with worn bearings, yours sounds
good.

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

Larry wrote:
>
> Hi all, I Wish everyone a merry christmas and a happy new year!
>
> I have a 93 xj with a 4.0 with a 116,000 miles on it and runs great good oil
> pressure, no oil leaks and the engine burns about a quart of oil between
> changes and has had regular oil changes every 3-4k and engine is clean. My
> Question is after it warms up a bit there is a rattle or knock coming from
> the bottom end and the oil pressure stays above 40 psi at above 1500 rpm and
> about 30 at idle other wise the top end seems quiet and with no passed calif
> emissions with no problems.I was wondering if I should be concerned or not I
> don't want to throw a rod on the road some day. I have heard other 4.0 and
> some seem Quiet and others have this knock without problems. I heard that
> there maybe some years of 4.0 with a problem with piston slap. Should I be
> worried or not this is my daily driver and with some minor off roading when
> going camping. I know some people that got more than 300,000 miles out of
> these engines!
>
> Any suggestions or comments will be helpful Thanks.

Re: Engine knock on 93 xj 4.0
 

Knocks are really deceiving....

I like to use an automotive stethoscope to help try to nail them down.

I usually associate low oil pressure with worn bearings, yours sounds
good.

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

Larry wrote:
>
> Hi all, I Wish everyone a merry christmas and a happy new year!
>
> I have a 93 xj with a 4.0 with a 116,000 miles on it and runs great good oil
> pressure, no oil leaks and the engine burns about a quart of oil between
> changes and has had regular oil changes every 3-4k and engine is clean. My
> Question is after it warms up a bit there is a rattle or knock coming from
> the bottom end and the oil pressure stays above 40 psi at above 1500 rpm and
> about 30 at idle other wise the top end seems quiet and with no passed calif
> emissions with no problems.I was wondering if I should be concerned or not I
> don't want to throw a rod on the road some day. I have heard other 4.0 and
> some seem Quiet and others have this knock without problems. I heard that
> there maybe some years of 4.0 with a problem with piston slap. Should I be
> worried or not this is my daily driver and with some minor off roading when
> going camping. I know some people that got more than 300,000 miles out of
> these engines!
>
> Any suggestions or comments will be helpful Thanks.

Re: Engine knock on 93 xj 4.0
 

Knocks are really deceiving....

I like to use an automotive stethoscope to help try to nail them down.

I usually associate low oil pressure with worn bearings, yours sounds
good.

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

Larry wrote:
>
> Hi all, I Wish everyone a merry christmas and a happy new year!
>
> I have a 93 xj with a 4.0 with a 116,000 miles on it and runs great good oil
> pressure, no oil leaks and the engine burns about a quart of oil between
> changes and has had regular oil changes every 3-4k and engine is clean. My
> Question is after it warms up a bit there is a rattle or knock coming from
> the bottom end and the oil pressure stays above 40 psi at above 1500 rpm and
> about 30 at idle other wise the top end seems quiet and with no passed calif
> emissions with no problems.I was wondering if I should be concerned or not I
> don't want to throw a rod on the road some day. I have heard other 4.0 and
> some seem Quiet and others have this knock without problems. I heard that
> there maybe some years of 4.0 with a problem with piston slap. Should I be
> worried or not this is my daily driver and with some minor off roading when
> going camping. I know some people that got more than 300,000 miles out of
> these engines!
>
> Any suggestions or comments will be helpful Thanks.

Re: Engine knock on 93 xj 4.0
 

Hi Larry
I have a 90 xj 141k, I bought it w/ 75k on it. About 20k later It developed a knock noticable when iddleing, a mechanic said that I should have it looked at but I was kinda short on cash. Never did get it checked out and it is still going strong..
Merry Christmas and a Happy New Year
Mike D

Re: Engine knock on 93 xj 4.0
 

Hi Larry
I have a 90 xj 141k, I bought it w/ 75k on it. About 20k later It developed a knock noticable when iddleing, a mechanic said that I should have it looked at but I was kinda short on cash. Never did get it checked out and it is still going strong..
Merry Christmas and a Happy New Year
Mike D

Re: Engine knock on 93 xj 4.0
 

Hi Larry
I have a 90 xj 141k, I bought it w/ 75k on it. About 20k later It developed a knock noticable when iddleing, a mechanic said that I should have it looked at but I was kinda short on cash. Never did get it checked out and it is still going strong..
Merry Christmas and a Happy New Year
Mike D