tricky cherokee overheating, been there done that.

[benztechnc]

Ok. I have a 1988 jeep cherokee, closed cooling system on a 4.0l engine. It constantly over heats, just to humble me I believe. I have replaced the radiator, both upper and lower coolant hoses, expansion tank and cap (it did help alot!) headgasket. When I had the head off, i did a visual inspection for cracks on the head and the block surface. I have flushed the system several times. I know that there is a minor leak at the thermostat housing now. And I do hope that fixes it. But deep down in side, i believe it's inside the engine or the block. Now, is it common for the head to crack (or for that matter the block) internally where I wouldn't be able to see it.

And if so, I have a crazy idea, and want to run it by you.. Could I clamp of the lower radiator hose, disconnect the upper, and install some brand of stop leak, and then pressurize it with shop air to maybe minimize the internal leakage, has anyone ever heard of trying something crazy like that.. I want all the feedback I can get. I am thinking of trying it in a week or two.

Thanks people.
josh.

 

[dandoc]

Take a look at this thread: http://www.jeepz.com/forum/showthread.php?t=20917

Perhaps applying that solution to your engine may solve your overheating problem.

 

[benztechnc]

That is a good idea, and I will price it out. Another question is this. I have a donor xj that I have been using to 'revitalize' both the other two running xj's. I stole the water pump of the donor for the one that is overheating, and tossed the original one. is there anyway to tell if either xj was originally a regular versus reverse flow water pump. I didn't find out till after that the xj's ran both at different times. both the donor and the overheating xj's are 88's.

thanks in advance.
-josh.

 

[t3chn1c0]

I found another article in which there were directions to "burp" the engine. In a closed system, it depends on the pressure to flow properly. If there is air trapped in the engine, that will stop it from flowing properly. The suggestion was to jack up the back of the Jeep, to raise the back of the engine, and remove the Temp sensor for the guage, and let the air out of the engine. Once all the air has been expelled, the coolant will flow properly, and the engine should stay cool.