Jeepers! Your fellow here needs help! 96 XJ overheating and it is driving me nuts. I have replaced just about everything - radiator, water pump, mechanical fan clutch. I even tapped into my electric fan and I have it running all the time. And FINALLY i took out the thermostat! Still the thing kicks it up to the 240s. I have flushed it twice. I have flushed it in an inclined and declined fashion trying to get the "trapped air" out. Still 240s. Any thoughts?
Verify the gauge with a known good master temp gauge. IR gun will tell you if the temp is close to 240, but a master in the coolant will tell you exactly what the temp is. Does the e-fan come on around 217 ish on the gauge if you don't turn it on manually?
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Just got a 1989 YJ too!
I had a similar issue I even replaced my sender and still read hot finally had a buddy who works at the dodge dealership look it over... After taking the reading a dozen times to be sure he kept getting a reading between 200 and 210... It turned out the sensor was bad to... Guess I needed to replace both the sender and the sensor now the gauge is reading almost exact with the ir gun... I did the same thing... Flushed, new fan clutch, new radiator and heater core, and new tstat... Guess atleast I don't have to worry about my cooling system for a while
Thanks fellas! Really appreciate your help and prompt response. I have replaced both the sender and the sensor too. I have new radiator cap (different than the one that came with the new radiator). Here are a few interesting facts that may help us decipher this:
1. After I did all that work, with a thermostat that opens at 160degrees, the Jeep was doing well. One evening after visiting with a friend of mine, I came out to drive home and noticed that I had lost all my coolant. I immediately realized that the bottom radiator hose was not clamped at the water pump end (dooooh!). I got it towed to my place and clamped the hose and refilled the system. Since then she has not been well!! I thought maybe I sucked in air so I did flush & fill X 2 since then. Still problem!
2. The reason I bypassed my electric fan was b/c it was not coming on (even with the AC running). After replacing the sensor, sender and checking the relay. Still no good. So I said F&*& it and bypassed the damn thing.
3. even after it has been running hot, I have opened the radiator cap (with construction grade gloves on so I don't scald myself) and the damn it is not trying to explode on me! Shouldn't it be under pressure? Is that not why you are not supposed to open it while it is hot?
4. Im simply stumped!
Thanks again fellas - looking forward for your replies
Yes it should... Mine vomits all over 20 minutes after it was turned off let alone running... I don't see how it could not build pressure but not leak coolant I would think that would go hand in hand... I guess you could go ahead and do a compression test on each cylinder someone said on here it doesn't always work as a 100% positive bad headgasket but it has in my past... But then I also had antifreeze in my oil...
The lack of a good water right seal has me stumped though unless you only had it filled half way or below so the only thing that happens when you open it is air rushes out
Edit: little research a guy had that same experience slight hot running and was able to open the cap with no drama... His was a manufacture defect in the radiator he replaced it and everything worked like normal
Hey thanks man! Yes I'm worried that it is the damn radiator! Man that is going be a pain in the *** to take that whole thing apart and put a new one. But I can't figure out what else it could be. I have replaced pretty much everything twice now except for the radiator! Here goes my weekend!
Yeah, removing the stat or using a lower temp stat is not a solution to overheating. A stat doesn't cool the engine; it just determines when the coolant starts to flow. The engine makes hot and the radiator makes cold. Fans facilitate radiators' cooling and water pumps deliver it. The stat is just a gatekeeper and you need one to help your engine warm-up to a proper operating temp.
Agreed gentlemen! No thermostat does not solve the problem. I was just at a loss and with a 12hr six days a week schedule, did have time to mess with it so I tried to short cut it. Two points to share with you: 1. The only variable that remained constant throughout this ordeal is the the radiator! I have done everything twice except touch the radiator. Could it be a defective one as one of you pointed out? Certainly! So I'm tackling that today! 2. Peculiar sign- after driving around and I **** the engine off the coolant flies back to the reservoir as expected. However it doesn't flow back in!! The next time the level is even higher; next time even higher to the point where it starts to spill over. It seems like there is a blockage. But where the f&$# is it? Radiator?
Well fellas- replaced the radiator just now and put back the thermostat. The thermostat is supposed to open at 160 but she climbs all the way to 210. At least she is holding between 230-240 when I'm idling with AC on and have my auxiliary running constantly. So still not what it is supposed to do but at least it's not climbing to 260.
So I'm gonna take it to the shop (which kills me cuz I do everything on my jeep and it's sign of failure when I have to involve the mechanics). I will have them figure this s#*¥€ out. I'm done!