2000 Cherokee Classic 4.0L overheating at idle AGAIN. This happened last year and had the system flushed for blockage, new thermostat, new radiator, new cap, new hoses and new fan relay. Worked fine till a week ago and it's doing the same thing, overheating at idle. Husband just installed a new rad AGAIN and a new water pump, old one had no fins left on it. Thermostat is opening just fine, still overheating... at witt's end... Please help

 

The head may be cracked which would super heat the coolant. Ask him if he can check for oil in the coolant or coolant in the oil?

 

have you got both fans running sounds like you might have air flow problem at idle with electric fan or fan clutch not working. dirty a/c coil restricting air flow, something to look at.

 

clutch fan ever been replaced

 

Yep, if u haven't replaced the fan clutch then u haven't replaced everything. A good fan clutch is needed most at idle and warm ambient temps.

 

Agree with the others.

The #1 cause of "temp creep" at idle ONLY is the fan clutch.

Often overlooked, inexpensive, and easy to replace.

Get a new one in there.....

 

Yup, fan clutch.

Make sure the head isn't leaking coolant into the oil though...possibility it *could* be the head.

 

My 96 XJ would be fine at speeds over 30mph, OR if I turned the heater blower on, but it would overheat at idle or low speeds otherwise. When I was parked in a parking lot idling, I watched the temp climb past the normal 190ish, and start heading for 220 and never heard the fan come on - so I made it a point to check the fan clutch. Here's how to check your fan clutch: If you let the jeep sit overnight and can still spin the fan blades easily with your hands the next morning, with the engine off and cold from sitting overnight, the clutch is bad. Mine did this and now I know what the random short-lived squealing I was hearing a few weeks ago really was! At first, I had thought it was a belt-tension issue from when I replaced my serpentine belt. Not a difficult replacement either and I found an OMIX fan clutch for pretty cheap, around $60 bux. Hope this helps!

also, I've been told the fan clutch is good for about 75k miles. Mine had over 100K when it finally died (as best I could determine being the 4th owner), but I think it was going slowly as it made noises for a few months before quitting.

 

Mine was fine on the higway but overheating at stop lights, problem was the fan clutch. It also a cheap fix. Thats most likely the issue especially if its never been changed. If the clutch fan is dead than the blade is not spinning fast enough at idle to cool the radiator.