Alright so I have had this issue twice with my jeep overheating within the last few weeks. It runs and drives fine at with the operating temp at 210 with the A/C on. However, when I'm parked at a drivethru waiting for my food it overheats. The temp gauge will peg to just under 260 and some faint white smoke will come through the vents. So I shut off the A/C and turn the heater on full blast and after a few moments the temp creeps back down to around 215. It seems to be fine after that. No misfires or any issue with it running. Like I said, it drives just fine in traffic waiting at stoplights and on the freeway it only seems to overheat when parked or idled for and extended period of time. I've checked the coolant level and its fine, it also looks to be clean. Any ideas on what it could be? Air in the cooling system? Time for a coolant flush? Clutch fan not coming on? Need a new water pump and/or thermostat?

Thanks.

 

Two things to check, Justin:

1. Is your electric fan coming on?
2. Is your fan clutch doing its job?

 

Do I simply just open the hood, turn on the jeep and let it get to operating temp to ensure those fans are coming on?

 

On my 97 XJ if I turn the AC on the electric fan will also turn on. You can try this to simply see if the fan is working if it is then let it get over 210, and shortly after it should turn on automatically.
To test the fan clutch open your hood, start the jeep let it run a bit then turn it off if your fan is spinning freely and with no resistance then your clutch is worn it shouldn't spin for very long once you kill the engine.
Another way to test the fan clutch is with the engine off give the fan a good spin by hand, if it has resistance and stops spinning relatively quick then the clutch is good if it free spins like its on bearings then its shot.

 

The fan clutch should be pretty much locked when the engine is hot. Open your hood, and peek around so you can see the fan spinning while you shut down the hot engine (or get a friend to shut off). The fan should stop almost straight away.

 

Sounds like a bad fan clutch. If you can spin it freely by hand 5 times or more with the engine cold, you need to replace it.To tTo


To test whether or not your fan clutch needs to be replaced, simply spin your Jeep's fan by hand while the engine is cold and if it spins freely 5 rotations or more, it will need to be replaced.
test whether or not your fan clutch needs to be replaced, simply spin your Jeep's fan by hand while the engine is cold and if it spins freely 5 rotations or more, it will need to be replaced. eTo test whether or not your fan clutch needs to be replaced, simply spin your Jeep's fan by hand while the engine is cold and if it spins freely 5 rotations or more, it will need to be replaced. st whether or not your fan clutch needs to be replaced, simply spin your Jeep's fan by hand while the engine is cold and if it spins freely 5 rotations or more, it will need to be replaced.