97 auto. 4.0 overheating

[MOHAWK225]

MY 4.0 HAS BEEN RUNNING 210 TO 220 THIS SUMMER. I flushed the radiator, engine, hoses and heater coil. when it gets over 210 the auto Transmission shifts late, or goes 2 gears. and sometimes does not go into Overdrive . I changet the water pump last summer late because the seal blew. I am wondering if there are 2 waterpumps for the 4.0 also?

 

[tarry99]

MY 4.0 HAS BEEN RUNNING 210 TO 220 THIS SUMMER. I flushed the radiator, engine, hoses and heater coil. when it gets over 210 the auto Transmission shifts late, or goes 2 gears. and sometimes does not go into Overdrive . I changet the water pump last summer late because the seal blew. I am wondering if there are 2 waterpumps for the 4.0 also?

Is it loosing water in the system?
Do you have to add water on a regular basis?
See any white smoke or dripping water at the tail pipe after it warms up?
Do you have the ability to pressure check the cooling system?
Have you checked your pressure cap?
Do you have a shroud around the fan blade?
Do you have a mechanical or electrical gauge?
Do to the fact you say the Transmission is acting up may sound like perhaps the radiator may be partially obstructed ..........but first look at the questions above, the ability for you to flush a radiator at home versus how they do it at a radiator shop is two different things.

 

[MOHAWK225]

Fan shroud is on. Electric fan turning correctly and comes on at 210. Electric guage. When i flushed i put a garden hose in hose and it just pored thru.. No blockage there.
I am going to get a seperate trand cooler this week but really dont think that is problem. I am wondering about the main computer timing the engine wrong. No leaks. No refilling the radiator/overflow. Have not really lookedat tailpipe. I do have a preassure kit. Will test it this week. I also have a temp cap on my gto. I will install that for cross check temp. I am looking at temp sending unit being bad and giving false reading to computer and causing a problem that does not really exist. Old thermostat opened at 204 with wifes candy thermoter on stove. New one 196. No real change except it takes a little longer ,i think , to overheat. Oreillys says there is onlt 1 pump for 4.0 , a serpertine.

 

[tarry99]

Fan shroud is on. Electric fan turning correctly and comes on at 210. Electric guage. When i flushed i put a garden hose in hose and it just pored thru.. No blockage there.
I am going to get a seperate trand cooler this week but really dont think that is problem. I am wondering about the main computer timing the engine wrong. No leaks. No refilling the radiator/overflow. Have not really lookedat tailpipe. I do have a preassure kit. Will test it this week. I also have a temp cap on my gto. I will install that for cross check temp. I am looking at temp sending unit being bad and giving false reading to computer and causing a problem that does not really exist. Old thermostat opened at 204 with wifes candy thermoter on stove. New one 196. No real change except it takes a little longer ,i think , to overheat. Oreillys says there is onlt 1 pump for 4.0 , a serpertine.

I guess the computer could be acting up..........does your motor "Ping" at all like its advanced?
Run a pressure check on the whole system and then make sure your Radiator Cap is popping off at the right pressure and if its old I would just replace it.
Still may be a bad gauge giving you false readings but you seem to think the Transmission is also runny hot.........just a trial and error type of fix.............sounds like your doing all the right things , let us know when and if you find the cause.

 

[MOHAWK225]

The Transmission is acting up. Maybe because it thinks it is hot.. The computer controls shifting. . The difference between 205 and 220 is hard to tell.. No smell or radiator overflowing/steaming. Ill swap radiator cap with one that is running at 200. I got a temp sending unit today.. And found my sons jeep has the same computer.. His acts ok. Going to do swapping one thing at a time. No pinging or other acting up on engine..ordered a water pump gasket so i can inspect inside it.

 

[Torxhead]

On a 4.0 that I had in a '96 Grand, it had two fans, one electric and one mechanical. if yours is the same setup, I would think it could be the clutch on the mecanical fan, or an issue with the electric one shutting off. At highway speeds it should cool down, if not, maybe a good time for a professional back flush.

 

[MOHAWK225]

Clutch fan at highway speeds. Its my understanding that the belt driven fan is not needed. Altho i have not changed it. At rest it has resistance and at idle it turns. Electric fan works normal above 210 indicated.
I've got work to do. Lucky it is an extra wheels that i can test one thing at a time.
Thanks

 

[kryptonitecj8]

My '91 '94 Jeep cherokees with 4.0's had two water temperature sensors. The one in the thermostat housing is for the gauge the other one at the back of the head is for the computer. I'm not sure if this is the same for your '97.

 

[kryptonitecj8]

Buy good quality sensors they're worth it.

 

[bondo258]

Electric fan turning correctly and comes on at 210.

​

Your electric fan should be coming on at the most the same temp if not 10-15 degrees lower than, your thermostat opens. You sound like you're t-stat is ok. 196 on a 195 is good. Remember, backpressure assists in opening it in a running motor.

What good is having the thermostat open into a hot, barely cooled radiator, only to have the fan come on when it is at the point of overheating? All it can do at that point is stay in the temp range your fan is set to.

You're putting hot coolant back into the motor by running the way you are now.

Automatic transmissions with coolers either internal or external require the fans to be on much more often (lower the threshold) than the verge of overheating the motor, otherwise you can cook your tranny, too.

 

[MOHAWK225]

Your post is confusing me...
My t stat opens at 195 about..
Into a rad that is cooler..
Then if temp sending unit senses 210 it turns on fan to cool radiator down as designed below 210 on the engine..

But this does not happen.

All my jeeps fans come on about 205 210.

At this time i have a rad cap that reads temp.. It says the rad water is 170 to 180 but engine is 210 to 225.
I changed the computer last night and plan to test that . Assuming the timing may be overheating the engine....
My next step is to pull water pump and compare to another...
I am really wondering if it has the veins og the v belt pump put on the newer single pump.
I put a rebuilt pump on last fallish.

 

[bondo258]

What sort of fan controllers are in your CJ, anyhow?

I assume you installed the drivetrain from a 97 into it. How did you cobble the various bits together?

Describe what you have, exactly.

 

[MOHAWK225]

Changed the computer last weekend and that did not help.
I pulled the waterpump today and it has about 1/8 clearence between the impellers and case. Got another from oreiles and it had about 1/16 clearence. I think this is it . Got a pic of 2 side by side but dont know how to post

 

[MOHAWK225]

Changed the water pump today and in 10 mile trip temp stayed below 212. And radiator showed 120. A longer trip will be in order on xway.

 

[mtnwhlr]

If this is on your 4.0 Cherokee that is the way all mine have run I don't think you have a problem with the cooling system.