Help! IT WON'T STOP OVERHEATING

[jeeperscreepers]

1077037

I have an 89 Jeep Comache Pickup that I got from my grandfather. It always had a problem with overheating. Before I got it from him he had the heads off and those were tested for leaks cracks ect. When we got it, it still ran hot, so we put in new fan clutch, thermostat, waterpump, and radiator. nothing happened. The weird thing is all the water is bypassing the radiator and giong into the recovery tank and the boiling out. If we clamp the two hoses the go to the tank off it seems to run fine. So we bypasses that entire part of the system and it ran ok for a couple of days, but when you take it above 70 mph the indicator light comes on. We have tried everything any help at all would be appreciated. Thanks [addsig]

 

[85zebracherokee]

1077038

Is the heater core messed up?[addsig]

 

[XJNick]

1077049

The weird thing is all the water is bypassing the radiator

How is that possible? The water pump's intake (suction side) should be connected to the lower radiator hose. So wouldn't the water have to pass through the radiator? Or am I missing something here.

just a thought

edited by: XJNick, Jul 18, 2003 - 05:30 PM[addsig]

 

[Hammrsigpi]

1077097

I have a similar problem. My fiancee has an 85 wagoneer that overheats in 10 minutes. We've heard numerous ideas, from the fan to the thermostat. She had her axle replaced in January, and soon after, this started. We get going, and you can hear the fluid bubbling after a few minutes. The steam/smoke smells a bit like burnt popcorn. I think it might be the thermostat because the reservoir is full. Any ideas?[addsig]

 

[Sound_Man]

1077102

I have a similar problem. My fiancee has an 85 wagoneer that overheats in 10 minutes. We've heard numerous ideas, from the fan to the thermostat. She had her axle replaced in January, and soon after, this started. We get going, and you can hear the fluid bubbling after a few minutes. The steam/smoke smells a bit like burnt popcorn. I think it might be the thermostat because the reservoir is full. Any ideas?

It sounds as though your thermostat is sticking or is in backwards. Open the thermostat housing and take a look and replace it. The spring side should be in the head not in the housing. Get a 54mm 180 degree thermostat and start from there. It is inexpensive and easy to do.[addsig]

 

[Sound_Man]

1077103

I have an 89 Jeep Comache Pickup that I got from my grandfather. It always had a problem with overheating. Before I got it from him he had the heads off and those were tested for leaks cracks ect. When we got it, it still ran hot, so we put in new fan clutch, thermostat, waterpump, and radiator. nothing happened. The weird thing is all the water is bypassing the radiator and giong into the recovery tank and the boiling out. If we clamp the two hoses the go to the tank off it seems to run fine. So we bypasses that entire part of the system and it ran ok for a couple of days, but when you take it above 70 mph the indicator light comes on. We have tried everything any help at all would be appreciated. Thanks

I had almost the same thing happen to me and it was my thermostat. Look at the post above on my suggestions.

Hope this helps[addsig]

 

[Hammrsigpi]

1077175

Thanks for the tips on the thermostat. Just one question, and I know it makes me sound stupid, but where exactly can I find the housing for the thermostat? :-? [addsig]

 

[Sound_Man]

1077187

At the front of the head where the top radiator hose is attached. There are 2 7/16" (I think) bolts that hold it in. :-D

edited by: Sound_Man, Jul 20, 2003 - 06:55 AM[addsig]

 

[Hammrsigpi]

1077235

Thanks for the help. Next stop, auto parts store for the thermostat, and junkyard for the fan clutch.[addsig]

 

[MudderChuck]

1077291

I have a couple of ideas, that are easy to check. The bottom radiator hose has a spring in it. If this spring is to short or missing, the pump at higher RPM´s will suck the radiator hose flat.
An after market thermostat gasket, will sometimes be missing the bypass hole, which is needed to keep the actual water temp. near the thrmostat actuator.
Don´t fill the canister all the way up, half full is enough.
Squeeze the top radiator hose, to move any air trapped in there (four hands is better than two).
WWW.madxj.com has a pretty good write up about the cooling system, in the engine section of tech. articals. I´m gonna do it to my 88 XJ in a few weeks.
Lastly, get a flashlight and hold it behind the radiator, inside near the fan and shine it outword(towards the front) and see if there isn´t some mud deep inside the core, that has turned to cement and won´t wash out.
[addsig]

 

[tripletsjeepin]

1077405

its a stuipid little thing but I have seen radiator caps go bad and not hold pressure and this can cause overheating. Just an idea.[addsig]

 

[K_K_PSI_GUY]

1077415

Ahh, that is excellent advice. Radiator cap![addsig]

 

[jeeperscreepers]

1077422

I just had the heater core flushed and the sensor that allows water to go into the heater core replaced along with new hoses that go to the top of the tank. I'm running out of ideas. I'm starting to look for a new engine for it so if anyone has one laying around let me know. :-x :-? [addsig]

 

[mburian02]

1077423

i am not real familiar with the comanche but if it is like the 87 cherokee the cap shouldn't be causing the problem but if the radiator cap is on the radiator then yes this will cause a problem by letting the heat boil the water past the cap up into the resevor due to it having a week spring causing an air pocket in the motor due to water starvation which causes it to over heat...if you are gonna change the thermostat make sure the spring side of the thermostat is facing down... if i am wrong correct me but in order for the cap to be the problem it would almost have to be a spring loaded cap and i know mine on my jeep is not but it could be the cap seal i guess....just my 2 cents [addsig]

 

[jeeperscreepers]

1077427

I forgot to say in my original post that on this engine, the system is sealed the only way to add coolant is to pour it into the recovery tank. There is no cap on the radiator or anything. Thanks for all the help so far.[addsig]

 

[XJNick]

99 TJ 4.0 Must Sell: jman

When you add coolant, it is best to pull off the upper radiator hose, pour in as much as possible, then top off the system through the recovery tank. Filling it only through the recovery tank gets air trapped in the system and takes alot longer :-D. Also be sure to run the heater while filling up the system or the core becomes a big air pocket. It sounds like there's trapped air or a bad thermostat installed (don't assume new means it's good)

-Nick

edited by: XJNick, Jul 22, 2003 - 03:41 AM[addsig]

 

[Hammrsigpi]

1077462

My fiancee's cap is spring loaded, and it won't come off. It could be just stuck or rusted, as it has one of those lift and turn systems. The top piece lifts, and the cap turns, but it won't come off, and I don't want to break it off. The reservoir is filled, and it appears that the fluid just won't go to the radiator itself.[addsig]

 

[XJNick]

1077463

The reservoir might be filled, but is the rest of the system? When I first tried to fill the system only using the reservoir, what happened was very little water would make it into the system. I had to 1)fill the reservoir full, 2) run engine for 5 min (or until it tried to overheat), 3) shut off and repeat. This took HOURS to properly get the system full :-O . That's why I just use the upper radiator hose as a filling point.

-Nick

edited by: XJNick, Jul 22, 2003 - 03:47 AM[addsig]

 

[hotnboderd]

frozen yoke

Hey all...
It seems my 93 has always run hot. Now we're in Tucson and I've had to shut the AC off d/t the temp needle getting too high. It's almost always at 210, regardless and it goes to 230 (+) with the AC on. I'm going to replace the radiator cap, then the t-stat will be next. Any other ideas? Thanks,
dq

 

[XJNick]

Hi, Welcome!

I'd first check the mechanical fan clutch for proper operation. Then flush the cooling system and put in new coolant. It does not sound like a thermostat problem, as a bad thermostat would most likely cause overheating regardless whether the A/C is on or not.

-Nick :!: