Overheating at an idle

[JRWinnett]

Okay , please help me out. I have been struggling with an overheating issue on my 93 XJ for around a year now. I have gotten to a point where it only overheats at idle. I've replaced the water pump, the radiator, thermostat (multiple times), I have flushed the cooling system thoroughly 3 different times til I had not a single sign of calcium in the water. I also replaced the temperature sending unit. I have not replaced the heater core, the clutch fan, and I am missing the electric fan. What do you guys all think should be my next plan of action other than ditching my Jeep off a mountain?

 

[Gotrdone]

Go to a junkyard or buy a new electric fan and get it back in there it should help a lot ! Might even fix the problem if it only overheats at a idle.

 

[JRWinnett]

Go to a junkyard or buy a new electric fan and get it back in there it should help a lot ! Might even fix the problem if it only overheats at a idle.

That's what I have been thinking, but I figured you folks would hopefully know. It makes it very hard to wheel, I end up having to stop every once and a while and let her cool down.

 

[Gotrdone]

Ya, without the electric fan the motor isn’t getting the air over the motor at a idle that it gets driving down the road -


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[Tim_MN]

Replace the mechanical fan clutch. Install the electric fan.

Consider installing a bypass switch to turn the e-fan on full-time when necessary.

 

[Runnin'OnEmpty]

Yeah, replacing the fan clutch made a huge difference in mine.
Even though the clutch will test OK, the fluid degrades and wear
occurs enough over time to allow the fan to slip more than normal, especially
at idle.

 

[JeepNoob]

Replace the mechanical fan clutch. Install the electric fan.

Consider installing a bypass switch to turn the e-fan on full-time when necessary.

^What he said.^ Fan clutch is most likely the culprit. AFAIK, the electric fan only kicks on when the A/C is turned on or the engine begins to overheat (somebody correct me if I'm wrong.) Easiest way to install a bypass switch for the fan is to install a switch to ground on the control/electromagnet side of the fan relay. HOWEVER, this will set a check-engine light with a code on '96+ OBD II XJ's, don't know about the earlier stuff, but I might have to try it on mine. Don't know how it does, but it will. So you might have to wire a second relay in. Do a Google search for it, plenty of information out there, plus wiring diagrams. Also, keep an eye on the coolant level. It is absolutely possible to slap the dreaded 0331 cylinder head onto an older 4.0. Al Gore's information super-highway INSISTED that H.O. and Renix stuff doesn't interchange, but...

 

[smccollamjr]

Electric fan only comes on with AC/defrost and somewhere over 210. You definitly need the electric fan, but as others have said you probably have issues with your fan clutch as well.