Auxillary fan not working and overheating

My 98 XJ overheated first time, since I bough it in July of last year (4.0L engine, 80K miles). I swapped the original cluster with one that has gauges about a month ago and the temp indicator was always at 10 o’clock position until now. It started with nasty valve pinging under light throttle and loss of power. It could barely climb a small hill. The temp went first time at 210 and creeped bit higher at the time when I got home. Soon after P0118 and P1287 error codes popped up. The coolant never came to boiling. It looked like the upper rad hose was warm when the heater hoses were so hot I could keep my hand on it for very short time.
Replaced the thermostat, the temp. sender on the t-stat housing, radiator cap, emptied the system and filled with fresh water/antifreeze. Let the remaining fuel burn and filled up the tank with 93 octane. The pinging is gone and power seems to be back, the temp. now stays at 11.55, just shy off 210 mark. The heater works fine. The main fan works fine, but the auxiliary fun never came on. Neither before, nor after new thermostat and temp-sender. The fan will not spin freely no matter the engine hot or cold. It does spin, but with resistance. There is no voltage on connector that connects the fan (with running engine).
It wont come on when I turn AC. But the AC never worked as long as I own the car.

Please advise how to diagnose the fan issue; should I replace the fan clutch, and which one should I get? NAPA sells two clutches for the XJ, one is slightly larger. Can it be relay and where is it?


Thanks a lot.




[FONT=&quot]P.S. I am thinking now that my car was running all this time with open stuck t-stat, because as I went through many earlier posts regarding the overheating issues, it appears normal operating temp. for most people is 200-210 centigrade Fahrenheit. As I remember from my high school days (we were taught how automobile works) the normal operating temp. for gasoline engine is 89 centigrade Celsius, or 193 Fahrenheit. So I think for this time of year, without a load it is bit high[/FONT]

210 is normal for an XJ. That is where mine runs. THe electric fan isn't suppossed to kick on until something like 217. If it's not boiling, it's not overheating (unless you are out of coolant). If you search, you can find resistance values for your temp sensor and for the gage to verify they both are working correctly.

Agree with winterbeater. You can jump power direct to the efan and see it it runs. Questions: Under what driving conditions did the temp go up, stop and go, idling, highway? How old is/was the coolant? Did you check the manual fan clutch? What brand new thermostat and what temperature?

Did you check if the fan is plugged in? On my 98 it has unplugged itself twice so I just wrapped a zip tie around it.

Screech said:

Did you check if the fan is plugged in? On my 98 it has unplugged itself twice so I just wrapped a zip tie around it.

Click to expand...

YUPPIE!! Duct tape would be the proper method of securing that connector! :doh:

the electric fan motor might be seized. Happened on my 98 before. Replaced it with a new one from ebay for $50 shipped. Has worked fine for about 6 months now.

It all started with 5 gallons of old gas that I put in the Jeep (the gasoline was sitting for long time in my garage). I got that nasty detonation. Could that cause overheating, malfunction of thermostat and subsequently destroy the t-sender? When I checked the resistance on the sender, it was in megaohm range with hot engine, and I got error code 0118 (hight voltage on the sender). The code has dissappered after new sender and 100 mile drive on 93 octane gasoline. I wonder if higher temp will improve the gas mileage, if the ECU decideds to shorten injection pulses with higher temp. So far I used third of the tank for 100 miles. That would be excellent mileage in the town. I never had more that 220-230 miles with full tank in town before.

I tried to run the auxillary fan directly from the battery (blue to "+", brown to "-" ). Nothing. Probably the motor seized. Will try to swap over the weekend.

Thanks again fellas

Yea, higher temp should improve mileage and yea, your e-fan must be toast.