Jeep Grand Cherokee overheating...

[Lyoungsjeep]

I have a 2003 Jeep Grand Cherokee...bought it in 05 and it has never given me any problems...except I had to have the radiator fan relay switch replaced about 2 summers ago: the fan was stuck on then it turned off and the jeep kept overheating quickly...
anyway no issues since then except this past fall/winter it began to over heat in drive-thru's and any time it idles for a few minutes. As long as I am moving at a speed higher than say, driving through a field, and as long as it's not overly warm outside, the temp stays good.
My boyfriend replaced the thermostat, still no go.
He seems to think it's a clutch fan??? Which I cannot locate on any parts website for my model of jeep....he does not think it is the water pump because as long as I am moving a little it doesn't overheat. But when the rpms are low, it overheats pretty quickly.
Any suggestions before I take it to a garage and spend a fortune diagnosing it???

Leslie

 

[SteelHeadz]

See list of recommended diagnosis and repair steps provided below. COOLANT LEVEL: Verify engine coolant level is OK before additional diagnosis and repair is considered. Add Mopar engine coolant as required. COOLING FAN ROTATION: Verify radiator cooling fan is rotating in the proper direction to draw air into the radiator core. Flat sheet of paper should cling to vehicle front grill area when the cooling fan is operating. If the air flow is moving away from the front grill area when the cooling fan is operating check for improper cooling fan connector pin assembly or shorted circuit wiring. Replace cooling fan if required. VISCOUS DRIVE COOLING FAN: Check viscous clutch drive cooling fan operation if so equipped. Replace viscous clutch as required. ELECTRIC COOLING FAN: Check related electrical components / circuit wiring / relay / connectors prior to hydraulic cooling fan replacement. Check for poor connector pin fit or wire harness chafing (rub through). Repair as required. PRESSURE CAP: Check cooling system pressure cap with Cooling System Tester . Replace pressure cap as required. THERMOSTAT: Check for cooling system thermostat stuck closed. Replace thermostat as required. WATER PUMP GASKET OR SEAL: Check for slight leak at water pump housing gasket / O-ring seal. Look for visible corrosion or slight leak point that may allow air to be drawn into the system which can eventually cause overheat. Replace water pump housing gasket / O-ring seal as required. WATER PUMP IMPELLER: Check for loose or damaged water pump impeller that can cause poor coolant circulation and possibly engine overheat. Replace water pump as required.

 

[Lyoungsjeep]

Thanks for the timely-mannered response!
The coolant level is consistently OK, maybe one of these other things will do the trick
I will definitely pass this info onto the bf who will be doing said diagnostics and repairs.

Thanks again!
Les

 

[Lyoungsjeep]

UPDATE:
My uncle and grandpa had a look at the jeep and fixed it! AFTER i remembered that the Radiator fan relay switch went bad two summers ago and had to be replaced...and my uncle tested the circuit to see if it was connecting...and it wasn't. "We" as in "they" put on a new switch (but had to drill a hole in the plastic beneath the plastic under the passenger headlight to access the dang thing) and the fan kicks on now--which was the issue. The radiator fan wasn't kicking in at all unless I was moving and air was blowing thru it.
Hope this helps future Jeep folk.
Thanks again for the suggestions.
Les

 

[Lyoungsjeep]

:d

update:
My uncle and grandpa had a look at the jeep and fixed it! After i remembered that the radiator fan relay switch went bad two summers ago and had to be replaced...and my uncle tested the circuit to see if it was connecting...and it wasn't. "we" as in "they" put on a new switch (but had to drill a hole in the plastic beneath the plastic under the passenger headlight to access the dang thing) and the fan kicks on now--which was the issue. The radiator fan wasn't kicking in at all unless i was moving and air was blowing thru it.
Hope this helps future jeep folk.
Thanks again for the suggestions.
Les