fails to defrost when it looses vaccum from the motor... may have pulled a vaccum line loose or created leak...

 

I have no suggestions but I feel your pain. I have the same problem with my 90 XJ. My mechanic thinks it might be the head gasket because he cannot find anything else wrong. I only paid $1000.00, so I'll try an additive to seal the head gasket. I'm not sinking $500.00 into a motor with 168,000.

 

210 degrees is not overheating. Most Chrysler vehicles have the fan turn on at 212 degrees and off at 205 degrees. I think your fan clutch is bad.

 

+1 on the fins. Maybe your head is warped too did you get it shaved when you did your headgasket it may be leaking still... I dont trust stock crap i got all autometer in both of the stang and the jeep. Get one of those heat seeker guns i forget what you call em its late...anyway you point it on something and it tells you the temp.

 

DO NOT PUT ANY SEALERS IN THE COOLING SYSTEM

that stuff is CRAP and it gunks the s*** out of the cooling system...it will not solve your problem only make it more of a headache.

 

this right here says blockage of some type, whether it be a bad t-stat or th water jacket itself. if you are over heating but the coolant hoses are cold then you are not moving fluid.

 

I had a little disc valve on the intake, that went to the heater box, on backwards. Its all good now.

Thanks!

 

I actually put a NEW cylinder head on, not just a gasket.

 

Mine has 189,000 on it. Not having a car payment anymore is awesome. I hope to put another 100,000 miles on it.

 

OK, I changed the fan clutch. I started it up and the neighbor that helped me set the head was here also. I was watching the temp gauge inside, while he was idling the engine higher. All of the sudden, he heard the coolant start to run. I guess the 2nd new thermostat needed a little heat to start working. The temp immediately dropped below 210.

Now it will go over 210, and then the aux fan will kick on. I can run the AC and the temp will stabilize about a needles' width above 210. When I turn it off, it drops to a needle's width below 210. It will rise slightly above when I idle after it hits operating temp. I reckon it is ok now. It just seems to be operating a few degrees higher than it was.

I wonder if the gauge now has an issue. Can I put another gauge in? With the heat gun, where do I point it, to find out if it matches what my temp gauge should be saying. The back of the block, or will the front work?

Thanks for all the suggestions and assistance folks. It is appreciated. A mechanic, I am not, but I have certainly enjoyed doing all the work I have. I feel like I have accomplished something and added a little self-reliance into another part of my life.

 

If the fan kicks on after it rises above 210 and shuts of after a bit it is working ok if your not leaking any coolant and the overflow tank reacts to the engine temp there is probably nothing wrong with it. the engine coolant temperature sensor tells the computer when to turn the aux fan on. Just starting the engine cold while you are on a hill will burp the system as the coolant expands if your radiator has air when cold maybe the tube going to the overflow is sucking air as it cools I just figured that one out by accident and it stays full now it is pulling coolant out of the overflow tank as it cools.

 

Well, I reckon it isn't fixed. I had to take my daughter to meet her mother for visitation, about a 2 hour drive away. Half way there, The temp gauge went to the 3/4 mark, and I had to shut down the AC. Fortunately, we are having a spring, so I just shut it off and let down the windows. It cooled down to about 210 in a few minutes. On the way back it got up to 1/2 way between 210 and the 3/4 mark a few times coming into towns, and stopping at lights.

Maybe I do have a water pump issue, even though it seems fine. That is the only thing in the cooling circuit that I have not changed. After spending about $1,500 for everything else, what is $30 for a water pump, right? Crap! I am at a loss.

 

Does it over heat while driving or just at a stop light/stop-go traffic?

I hate that you are throwing parts at it but it sounds like the pump is not moving the coolant through the system.

 

x2

 

I didn't start off throwing parts at it. A mechanic did some type of CO2 test with a dual-baffled-blue dye-turkey-baster looking thing, on the radiator filler. He said it was turning green, but it didn't look like it to me. He also said the head was cracked. Instead of paying them $1,500 to do the job, I bought a new head from a place that does them in Atlanta for parts houses and shops, and only paid $253 for it. The rest was just that I decided it was apart, to go ahead and change hoses, sensors, etc, and come out cheaper than just the head through a mechanic shop.

After that didn't work, then it was mentioned that even though the water pump shaft was not loose, and I was not leaking, it still may be the water pump. I said, "thanks for the info on the $35 part, after I spent $1,500 on the rest." He could have recommended the less expensive alternative first, but then that wouldn't net them as much money, I guess.

It is mainly overheating while driving at highway speed (55-60). I guess, logically, that would indicate sufficient movement at idle (around 600 rpm), but the fins are not keeping up with the flow while I am doing 1800 rpm's, at 60 mph?