HOT HOT HOT Double Check
 

OK...so the work continues on the Poor MJ.
(89', 2WD, Auto, 76K, SWB, 4.0)

https://www.cherokeeforum.com/f88/oh-poor-mj-193930/

Running, have driven but just in the neighborhood.

After dash swap Monday have been forced to watch the temp gauge CLIMB frighteningly. Previously, the idiot light NEVER came on. Have attempted to monitor with my HF IR heat thermo but not really sure what I should be seeing and then I shut if off before I watch it melt down ( as the gauge continues to move UP the temp scale).

So...NEW Waterpump (NAPA), Thermostat (Stant), Lower Rad Hose, Pressure Cap (NAPA Volvo).

Has been flush SEVERAL times (Heater core as well) since the truck sat for god knows how long. Radiator flushed separately but hasn't been sent out to "professionals"...yet.

AUX fan never kicks on. Water sending for gauge install new BWD from AutoZone.

Now have new Hayden Fan Clutch to install tonight and further attempt to test the AUX fan. Still originally fan. COULD swap the one from my 97' XJ in for testing if it proves bad.

Have I overlooked the obvious someplace?

Use that IR thermometer on the thermostat housing. It shouldn't exceed 220°F, esp. if the aux fan isn't kicking on.


I think replacing the temperature sending unit with a guage-specific unit might help- the resistance of the idiot light sending unit could be very different.


Test your auxiliary fan by jumping 12v directly to it and then work your way back from there- it would be great to know if the ECU also feels that its getting too hot... I'd check the relay and fuse for it too.

Just too chicken to let it run and attempt to believe the gauge and or sender is bad. Stupid I know.

The sender is a brand new gauge sender..BWD is the brand.

Around here everyone sells the same thing. Autozone, Advance, O'Reilly's, NAPA.

Connected AUX to battery source and it spun so it is less questionable. But is still not coming on. Cleaned the crap out of the Relay socket ( next to the EGR solenoid on LFT fenderwell. Had already cleaned it but had not checked the underside. OMG that factory grease crap is all over that fender-well now between that and the headlight harness connection that I already cleaned.

The new fan clutch seem to help but only slightly at first. Then the temp just seemed to almost run away.

I may pull the whole gauge cluster back out also. The fuel gauge appears to be non-functional now as well.

And I know the closed system isn't the terrible monster some think but man it is so nice to be able to leave off that radiator cap and watch the system WORK right before your eyes.

OH the joy of resurrecting something that someone else abused/neglected.

as noted, use an IR thermometer to verify temps. that will confirm if the gauge is correct. That should be the first step.

Agreed.