Help with cooling problem
 

I have a 1993 4.0L Cherokee with about 120,000 miles. Lately it has been
having cooling problems (the weather has been hot, but I have had this
vehicle for 6 years without a cooling problem). Any suggestions to help
with cooling?

From doing searches, I think I would like to:

-Flush, and reverse-flush the cooling system.
-Get a new thermostat (I have noticed they are rated by temp range, and
would like to know what range you would recommend. Is it practical to
switch thermostats for when the weather changes? Live in Nebraska, so temps
change greatly from season to season.)
-New radiator (pressure) cap.
-New lower radiator hose (the current is original, and feels pretty soft).

Any other suggestions? Any help is greatly appreciated. Thanks in advance.

Re: Help with cooling problem
 

"bpn" <bpn@nomailforme.com> wrote in message
news:vg3tesc7umbs21@corp.supernews.com...
> I have a 1993 4.0L Cherokee with about 120,000 miles. Lately it has been
> having cooling problems (the weather has been hot, but I have had this
> vehicle for 6 years without a cooling problem). Any suggestions to help
> with cooling?
>
> From doing searches, I think I would like to:
>
> -Flush, and reverse-flush the cooling system.
> -Get a new thermostat (I have noticed they are rated by temp range, and
> would like to know what range you would recommend. Is it practical to
> switch thermostats for when the weather changes? Live in Nebraska, so
temps
> change greatly from season to season.)
> -New radiator (pressure) cap.
> -New lower radiator hose (the current is original, and feels pretty soft).
>
> Any other suggestions? Any help is greatly appreciated. Thanks in
advance.
>
>

Those are all good steps, but change the UPPER radiator hose, too.

A soft radiator hose can collapse under pressure, and may be restricting
coolant flow.

You don't mention when it runs too hot .... high speed, stop-n-go? It does
make a difference.

With the vehicle off and cold, try to turn the radiator fan blade. Should
turn easily. With the vehicle off and HOT, try to turn the fan blade. It
should be near impossible. If it still turns easily, your fan clutch is
shot.

Last resort, but the quickest and easiest for me, was to replace the
original radiator with a good 3-core. Haven't had a problem in my '87 4.0
since.

Larry

Re: Help with cooling problem
 

>Last resort, but the quickest and easiest for me, was to replace the
>original radiator with a good 3-core. Haven't had a problem in my '87 4.0
>since.
>

Replaced just about every bit of the cooling system on son's 95 XJ--the 3-core
Go-Dan radiator was the cure--bought from Radiator Doctor--like eBay Item #
2421415729

Paul B.
01 XJ

Re: Help with cooling problem
 

bpn wrote:
> I have a 1993 4.0L Cherokee with about 120,000 miles. Lately it has been
> having cooling problems (the weather has been hot, but I have had this
> vehicle for 6 years without a cooling problem). Any suggestions to help
> with cooling?

Sounds like something is busted all right. I can't get
my 4.0 over 210 degrees even climbing hills in triple
digit desert temps with A/C on. Fan sounds like a
hovercraft sometimes, but 210 is it.

>
> From doing searches, I think I would like to:
>
> -Flush, and reverse-flush the cooling system.
> -Get a new thermostat (I have noticed they are rated by temp range, and
> would like to know what range you would recommend. Is it practical to
> switch thermostats for when the weather changes? Live in Nebraska, so temps
> change greatly from season to season.)

The standard setting isn't broken...

> -New radiator (pressure) cap.
> -New lower radiator hose (the current is original, and feels pretty soft).
>
> Any other suggestions? Any help is greatly appreciated. Thanks in advance.

Unless that lower hose restricts flow, it is probably not
the culprit, altho it should be replaced as you poke
around.

The radiator itself may be getting clogged, the
serpentine may be slipping, or the water pump may
be having a bad day. After you do the flush,
radiator and water pump flow check with a new
standard thermostat, then it might get to worse
news if a pinhole in the head gasket is allowing
exhaust heat to get to the water.

Re: Help with cooling problem
 

"mikltaz" <mikltaz@hotmail.com> wrote in message
news:Phudna-7_Ip1pp-iXTWJjA@comcast.com...
> let's take a look at this. jeep is ten years old, has 120k on it.
perhaps
> you need to replace thae radiator with a three core, replace the water
pump,
> all of the hoses and properly fill it. check the mechanical fan clutch
and
> make sure it is good. let's face it, its time to replace it.

Thanks for all of the input. How tough is it to replace the radiator on
this model? I am no mechanic, but I have done other minor work on this
Jeep. But am not affraid to tinker (I also have a mechanic buddy that would
help me do it for a couple of beers). Also, I found the 3-core Go/Dan on
Ebay, and they mention the open and closed system. Not excatly sure what
that means. Again, and info is appreciated.

Re: Help with cooling problem
 

> Thanks for all of the input. How tough is it to replace the radiator on
> this model? I am no mechanic, but I have done other minor work on this
> Jeep. But am not affraid to tinker (I also have a mechanic buddy that
would
> help me do it for a couple of beers). Also, I found the 3-core Go/Dan on
> Ebay, and they mention the open and closed system. Not excatly sure what
> that means. Again, and info is appreciated.
>
>

Sorry, forgot to mention the water pump was replaced a couple of years ago.
So the parts list I am looking at includes:

-3-core radiator
-Upper and lower hose
-Thermostat
-Radiator cap

Any other suggestions. I don't like trying just one thing and seeing if
that works. I would rather replace all the probables and have it done.

Re: Help with cooling problem
 

First, drain a little coolant out then add about 1/2 box of Calgon water
softener to the radiator. Now top off the radiator. Calgon water
softener works great for breaking up hard water deposits often found in
cooling systems. Calgon will not harm the cooling system like some other
popular radiator flush products. Don't be afraid to drive around for a
few days with this stuff in the radiator. it wont hurt anything. At
work, we would run Calgon for a week in our Caterpillar earthmovers,
loaders and dozers before flushing them out. It takes about 3 times to
flush out all of the old coolant from the engine and radiator. Drain out
old coolant, fill with clean water, bring engine up to operating
temperature to open the thermostat then drain it out again after it has
cooled off a bit. 2-3 times ought to get it. Look inside the core. If
there are still deposits of......stuff around the tubes inside your
radiator, you might need a new core. Now, install a new 195 deg.
thermostat, upper and lower hoses if needed. Also, check the heater
hoses, now is a good time to change them if they might be in bad shape.
Always use new hose clamps! Old clamps even though they might look good,
can and do come apart...not good. New camps are cheap compared to a
melted engine. Finally, fill with 50/50 anti-freeze, distilled water
mix, check for leaks, fire up your motor while still checking for leaks
and top everything off. I know this sounds like a lot to go through just
for a radiator flush...and it is. But it's done right. Or, you could go
out and pay someone to do a 1/2a$$ job...and hope for the best.

I Jeep, therefore I am...

RollOver Pete...
Check me out at:
http://community.webtv.net/SLAMBANG/RollOverPetesPage
http://7slotgrille.com/jeepers/yj/pete/