MrStratPants

Sorry for the novel, but I want to be through in my explanation:

Took 98 XJ to mechanic 2 weeks ago for brake work and overheating issues. Mechanics had my vehicle for a week, said they couldn't figure out the overheating issue. They said electric fan was bad and need replaced and it needed flushed. So they replaced the fan and did a flush. It was still getting hot.

In their guesswork they also replaced my radiator, and water pump (which I ended up not paying for). They said with a infrared thermometer it was showing to only be hot right in front of the water pump. Said It was drivable as long as I wasn't going to long trips. They said the head gasket was fine. I don't have any symptoms of a blown gasket as far as I can tell. So since I just needed transportatoin for the 10 miles to work, I picked her up and have been driving her sparingly.

I noticed the coolant was rusty again, so I decided to clean it myself in hopes that it just had too much crap in it.

So I began my journey:

I pulled the inlet/outlet hose on heater core and did a flush the other day, (got all kinds of black stuff out of it) in preparation for a full system flush.
Yesterday I spent 6 hours flushing the coolant system myself. Bought the Prestone flush and fill kit.

Here is what I did:

Flushed with garden hose til water came out clear, then started jeep let it run til the water came out clear.

Drained from lower hose, and filled with 2 bottles of Prestone Radiator flush+cleaner. Topped it off with distilled water. Drove 20 miles, and let it run in driveway for an hour.

Flushed again with garden hose til water came out clear, then started it to clean the block, and let it run til water came out clear again.

Drained from lower hose, filled with distilled, let it run for 10 minutes, drained, filled with distilled, let it run for 10 minutes, drained from lower hose, filled with distilled, and let ir run, then let it sit for the night.

This morning came out drained it again, and the water was brown again, so I decided to flush with the hose one more time (which I didn't want to do) until I had clean water again. Drained from lower hose once more.

I also pulled the overflow and cleaned it, it had like an inch of mud/rust in it.

Installed a new Stant Premium 195* tstat and gasket.

Filled radiator with 1 gallon of straight Prestone, and then topped it off with 50/50 mix in radiator and overflow.

Let it run for 30 minutes, then drove around for an hour. It was great, held right at 210*, I was so happy, I was like, "I did it!". Then I decided to turn on the a/c to check it out. With the a/c on it rose a couple degrees while driving, but was fine. When I parked and sat for 15 minutes, it shot up and said I was overheating. This is driving me nuts.

I would like to thank everyone on all the forums from the stuff I have read, been an extreme help to me so far. XJ owners rock!

Anyone have any ideas?

djb383

Fan clutch is about the only thing not replaced.

"it was showing to only be hot right in front of the water pump"......not exactly sure what that means. The water pump is where cooled water enters the motor. Hot water exits the motor above the water pump at the t-stat housing.

Epk5150

Could it possibly be a bad temp sensor?

RTorrez1

You keep saying that it is getting hot. But you never say how hot. What is the temp you are getting? Borrow a I.R. temp gun and verify your temp yourself, aim the temp gun at the t-stat housing and let us know what it is reading compared to what the dash gauge is reading.

CCKen

When sitting still and it gets "Hot" does the radiator electric fan kick on?

djb383

New rad cap???? A bad one will allow coolant to boil at a temp well below overheating temp.