mjazzy

Hi,
Sorry I'm new to the forum and I was wondering if anyone can help me. I Have a 1998 Jeep Grand Cherokee 5.9 Limited v8 with around 134,000 miles on it. I've been having an overheating Issue lately and I can't seem to figure out what the problem is. The fan turns on the second I switch the key to start and it stays on while the engine is running which is perfect because it has always been that way. I drive about 15-20 minutes and Tempreature rises slowly until it reaches 225. It's the same problem with or without the A/C being used. I installed brand new Mopar Thermostat, brand new water pump & I also have new oil pump. I pressure tested the radiator and there are no leaks at all. I flushed the radiator & filled it with Antifreeze/Coolant. I checked the head gasket for leak and there is none. Heater works perfect & coolant level is still the same for over a week. I know my car has a two speed electric fan because I had it replaced just last year but I really can't tell if the high speed fan is coming on when it is supposed to. I've checked the relayes on the passenger side inner fender and they both Have "HI RAM" written on them. I switched the relayes to see if the fan turns on and it still works. "Coolant Sensor Bad" message shows on the info center sometimes but I don't know if that has anything to do with the problem.
Any help would be much appreciated!PLEASE!

Willys55

Has it ever boiled over? If not maybe the guage is not correct, I would put a mechanical guage on it to see if the temp is really that high.

ol"blue

Welcome to CF. I'll send you a Private Message.

bluvette28

My grandfathers jeep did the same thing and it was the water pump he had heat even though the water pump was bad.

mjazzy

Willys55, Ol"blue & bluvette28! Thank you all for your response!

Car never boiled over and coolant seems fine in the tank. I hope the temp gauge is the one not giving the write reading. Water pump was installed few weeks back and everything was fine till now.. so mechanical temp guage is my next step to get the actual reading!

Thanks again to all of you!!

ol"blue

We're here to help if you need it.

SH2004

I have the same problem. I had my "coolant sensor bad" message pop up on my dash computer. I just replaced the coolant sensor a few days ago and the light is still blinking on my dash computer (randomly it seems). I also have my temperature gauge running right around 230 degrees. Have you figured out what is causing this? I think I'm going to do a coolant flush and replace the thermostat to see if that helps