Overheating??

[JeremyPhillips]

Apologies in advance if I'm posting questions that seem elementary.

Took my first trip with my 1991 M1098. Don't have a tag or title but couldn't wait any longer. After about 15 miles to some farm land I noticed that I was exceeding 240 degrees. I was surprised there wasn't a warning light that indicated excessive temperature. I did not smell anything funny, nor did I notice anything out of the ordinary except for my temperature reading. My gauge goes to 240 but before I could turn around it had exceeded that range. Looking back I should have paid closer attention to my gauges.

Any thoughts on where I should begin?

 

[gimpyrobb]

IR temp gun to verify it was/is that hot.

 

[63foxtrot]

unplug the time delay module/black box by the washer bottle your fan should turn on. your temp sensor could be bad.

 

[Action]

yeah, could be a bad gauge, dirt covering radiator, plugged radiator, bad thermostat, etc.
As stated above, unplug the connection near the washer bottle to the black rectangular box that is sitting there. That will make the fan run constantly, assuming that system is working OK.

 

[papakb]

There's a very good test procedure for the cooling system in the manuals that works well. If you haven't downloaded them then do so immediately. Unfortunately people don't know it's there. Search around and it'll help you resolve your issues. The cooling system can be a PITA to troubleshoot. You also need to understand where all the applicable sensors are. The one behind the alternator is just for the temp gauge. The fan sensor itself is on the top of the engine. It tells the solenoid valve when to shut off and energize the fan clutch. It's backwards from the way conventional systems work and makes the fan run when it turns off. This is why disconnecting the time delay module actuates the fan. The thinking is that if any of the components fail the default mode is to run the fan all the time. This is a nuisance because it's noisey and sucks about 10 horsepower out of an already underpowered system. The cooling system fan solenoid should de-energize (turn on) around 230 degrees and then energize (turn off) around 180 degrees.

Kurt