jonnyb78

Hi all,

I have a 00 xj that has been running hot. Its not running in the red but hot enough to start to steam up. The first time it did it I was running late for work and coundnt stop to let it cool. It was only slightly over 210 so i didnt think it would hurt anything. I was literally 5 min from where I was going. The guage didnt go any higher than it was. Once it cooled i realized that i was very low on coolant. I added a gallon of coolant. I figured that was part of the problem Well it still ran hot on my way home. Engine runs great. No smoking, no oil in the antifreeze no milky oil and no evidence of exhaust gasses going into the antifreeze. I next changed the t stat. No difference. As i was driving around the waterpump started making a horrible noise. Got it home and pulled it off and replaced it. The guy gave me a different t stat to make sure I didnt happen to get a bad one. put that all back together and flushed out the whole system. Still exactly the same condition. I didnt know where to go from there so I brought it to my mechanic. He said the hydrocarbon levels were really high and it was definitely the head gasket maybe the head is bad too but it had to be sent out. I couldnt afford his price so i pulled it apart myself. The gasket looks like it is perfectly fine. The machine shop just called and said the head checks out fine but it does need a valve job That shouldnt have any affect on my issue though. He also said the engine is a 96 according to the casting # so the po must have had it replaced. Anyway, now im not sure what to do at this point. Any ideas of what to check from here? Sorry for being so long winded, I just wanted everyone to have all the info. It supposedly has 116xxx miles but since the engine was replaced i dont have a clue what it really has

jonnyb78

Also changed the electric fan about a month ago. I had been looking for leaks. No evidence of leaks anywhere. When I refilled my lost coolant, I had been keeping an eye on it and it didnt go down any. That baffled me too

RTorrez1

Where did you see the steam coming from? Maybe you have a leak that you haven't seen or even just a bad rad cap.

jonnyb78

The hood was closed cuz I was driving but it was coming out both sides of the hood and also from the vents inside

jonnyb78

After a good amount of research I have found out that hydrocarbons is unburnt fuel and is a problem with the valves. The machine shop did say the head needed to be rebuilt so that explains that but that should have nothing to do with overheating correct???

Turbo X_J

Did you perform a compression test before you tore in to it?
ETA:
Have you verified temperatures with an IR thermometer?
Are you sure the water pump failure isn't the cause of this whole situation? First the bearing gets sloppy and takes out the seal, then if left unchecked the bearing wipes itself out.
Have you sent a sample of the oil off to Blackstone?

jonnyb78

I did check with IR temp gun. The waterpump was replaced with the same exact issue. I did not do a compression test. I asked the mechanic that diagnosed it as the head gasket if he did one. He said he did not but the high level of hydrocarbons was an indication of a bad head gasket