Weird overheating issue. Mechanics couldn't figure it out...

[Mudderoy]

I had "heat creep" on my 98 XJ for years. I'd have to drive 12 miles at 60+ mph and the temp would start creeping up. Finally fixed it. Three key areas.

Radiator, factory Mopar.
Replaced heater core (thanks Matt!)
Air flow. With aftermarket winch bumper needed more of an air dam to force air through the radiator.

I can drive 80 mph in 96 degree air temps. If I dog it a lot temp will rise but it holds and will cool over time.

Oh, and this will curl your hair. The old 4.0 and the new 4.0 had the same heating issue. At they are two completely different motors.

[MrStratPants]

I swapped out the fan clutch and coolant temp sensor last night.

I did some driving today, without the ac and she did perfect on highway and in traffic on surface streets. After a while I drove for a while with the ac on full blast on the highway, and in traffic on surface streets, still did great.

I am hoping we got it licked and she'll be good for a while longer!

[slvmart]

Good to hear !