few things ive heard.. overheating

[88swampedmj]

ive heard that if the wrong year waterpump is on my truck that the blades spin differently so it would make the water pump perform backwards..

is this true? if so what should i look for to know if this is my problem?

the one thats on mine seemed fine but is it the wrong year?

 

 

timing.. someone told me timing will make a vehicle run hot but.. 4.0s don't really have an adjustable timing do they?

 

ive had my truck for almost a year and it overheats everyday...

 

i flushed the rad.. new thermostat...new coolant....

 

it won't cool down

[StevenH]

Most serpentine belts run on the water pump on the opposite side of the belt and the water pump does turn backwards, they are reverse rotation pumps.

[Wildman]

Yes, the 4.0 water pump runs counter clock wise, I'm thinking the 2.5 is the wrong pump?? Correct me if I'm wrong.

 

Check out this site, might help -

 

http://www.lunghd.com/Tech_Articles/Coo ... gnosis.htm

 

And just replace "Cherokee" with "Comanche" :D

 

The timing is done thru the ECM, No adjustment on the timing, unless the distributor is in the wrong locating (gear wise, tooth off)

 

Even thought you flushed the radiator, it could be plugged, and not cooling, and if it's 20 years old......well, could be time for a new one. Kind of one of them, spend $100 for a new one, and solve a lot of problems.

 

The fan clutch could be shot, and not pulling air as it should too.

 

Check out that link and see if anything helps your problem.

[HOrnbrod]

Yes, the 4.0 water pump runs counter clock wise, I'm thinking the 2.5 is the wrong pump?? Correct me if I'm wrong.

 

Check out this site, might help -

 

http://www.lunghd.com/Tech_Articles/Coo ... gnosis.htm

 

And just replace "Cherokee" with "Comanche" :D

 

The timing is done thru the ECM, No adjustment on the timing, unless the distributor is in the wrong locating (gear wise, tooth off)

 

Even thought you flushed the radiator, it could be plugged, and not cooling, and if it's 20 years old......well, could be time for a new one. Kind of one of them, spend $100 for a new one, and solve a lot of problems.

 

The fan clutch could be shot, and not pulling air as it should too.

 

Check out that link and see if anything helps your problem.

 

Agree with all the above Bob posted. :agree:

 

However, if none of the above works, check for a clogged cat. If you still have the original, it could be the cause of your problems. I did all of the above; replaced the entire cooling system, but the cat turned out to be cause for me.

[Wildman]

Gee......Thanks Don ;)

 

And I'll second your motion on the Cat, very over looked item that causes odd problems. And easy to resolve.

 

Another one of them 18-20 year old items that should be replaced.

[88swampedmj]

are the original cats the big long cylindrical ones?

[HOrnbrod]

are the original cats the big long cylindrical ones?

 

I'd forgotten what the cat looked like since I haven't had one on in years so I took a peek at my parts manual. The MJs came from the factory at the time with either a catalytic converter (15) or a resonator (17). Didn't know that. Sounds like your rig has the resonator.

 

Image Not Found

[Eagle]

The water pump problem is that Jeep sold the 4.0L engine in the Cherokee and Comanche while they still offered the 4.2L in the Wrangler. ALL the 4.0L applications used a serpentine belt, but the 4.2L used the standard belt ... and a water pump that doesn't spin in the "reverse" direction. Since the blocks are essentially the same, you can install a 4.2L water pump on a 4.0L engine and vice versa.

 

The 2.5L engine in the XJ and MJ came with either a standard vee belt or a serpentine belt, depending on options. I don't know if those water pumps are the same as the 4.0L or 4.2L pumps, but it wouldn't surprise me.