I just got my Jeep and it drives great only problem is when I idle for to long it starts heating up. Never really past 210. I know everyone says at 210 the Jeep is not overheating but when it reaches this point the coolant in the reservoir is boiling over the reservoir cap. I did not think coolant has the same boiling temperature as water? But I used a Laser Temp gauge from my pizza oven and it seems the gauge is accurate. My fan does not kick on even if the ac is on. The thermostat is brand new and so is the water pump. I was going to just take the thermo out. I always have run without one on my older vehicles. I live in Houston I don't really have to worry about the engine being cold lol. Any help would be much appreciated.

 

Its an 89? So its a closed system?? Sounds like your cap on reservoir bottle is shot, get a new one from your dealer. Also fix that fan, make sure its good by running 12 volts right to it. As long as your ac compressor is working your fan should come on as well.

My fix was, new radiator, thermo, clutch fan and exhaust from cat back. now its happy.

 

Yes its an 89. I'm not running a cat lol. Have to go to towns that don't do emissions. Tonight hopefully I can hot wire the fan and rip out the thermo. Thank you for the help.

 

You are going to run without a thermostat?
Shouldn't really do that. It's better to keep things at the designed temperature.

It would be easy to hot wire the fan, but better to find the problem and fix it so that the fan comes on and off properly. Then again, you might hot wire the fan and discover that it doesn't work at all!

 

Ya I was only hot wiring to see if it works. And ya I hear the no thermo can be bad but on my 76,84 fords and 95 chevy I pull them out. I just was gonna try on the Jeep and if it works then ok if not ill keep searching and install it again.

 

I would just change out your system to an open system. I just changed mine out last week it was pretty painless. I put a radiator from a 1992 XJ in it with a new coolant valve also from a 1992. I upgraded the thermostat housing as well, since the 1992 fan thermostat is located in the thermostat housing. I am waiting on my Hayden products adjustable fan control that will fit in the new thermostat housing, which will allow me to control when my fan turns on and off.

My jeep has been running great with out the crappy closed system, oh and I forgot you will need a overflow bottle. I modified my old pressurized bottle since it had a nice mounting location already.