Trail Overheat

[acschilling]

Last Thursday on the trails my 92 OHV overheated and shut down..oh **** I thought. After trying a couple of times to get it started, we popped the hood and let it sit for about thirty minutes. After letting it sit, it started back up and we got it down the trail and back home from the mountains with no further issues. I can remember though, on the way climbing the highway to the trail the engine seemed to cut-out for split second (twice) then acted normal again.

I'll try and give as many details about my truck and what we noticed/tried/tested/hypothesized might be the problem. First off, the temp gauge in the truck had been on the low side for quite some time..it was suggested that I should change the sensors as it seemed abnormal, so I did. Both of them. The temp gauge will hold about the "N"\"O" spot now (it would never reach the NORMAL letters prior to the sensor switch. Can bad a ECT(s) cause a shutdown on a 92?

Fan Clutch: This seems to be my latest suspect. I am trying to research how a fan clutch is supposed to properly work (cold:free spin EO; hot:clutch engaged, no spin; EO). Is this correct? When the engine is started from cold the fan spins, but I can't tell if the status of the clutch changes upon warm-up. I have never driven another Firsty.

Fuel: On the trail I was able to hear the pump prime (pump only about 18 months old). Fuel filter a year old. Leaky EVAP line on top of the tank fixed last summer. We took the service cap off the fuel rail and were able to spray gas out of the hole (so fuel is getting to the rail). I was thinking fuel pump relay possibly (especially when laying on it while climbing the mountains; heat spreading contacts, too, maybe?) I have also read that it is extremely difficult to vapor lock these engines (it felt pretty hot damn hot under there though).

$0.02 and/or facts please. Sorry about the long post, guys.

 

[Sedition]

When the engine is warm enough for the fan clutch to engage you will easily hear the fan from the drivers seat as you accelerate, it sounds kind of beefy.

The fan clutch is probably the cause of your overheat if your cooling system is full and holding pressure. IMO belt driven fan clutches are garbage. I'm rebuilding my engine at the moment and won't be reinstalling my belt driven fan because i'm going electric.

I had an issue with my fan clutch not engaging so I unattached the coil spring on the front of it and turned the center pin as far as it would go in one direction. This caused the fan clutch to be engaged all the time as a temporary fix until I was able to do my engine rebuild.

Oh, and while your in there I recommend changing the thermostat as they are cheap and like to fail when they are old.

 

[acschilling]

I've heard good and bad about e fans on the trail,, though the fan clutch was my latest suspect..its probly twenty years old too. Thanks for the reply Sedition. By the way do you know if the PCM is able to shut down the engine if overheated?

 

[Sedition]

I don't know but some engines can stall when overheated because some parts expand to much due to overheating. I did that do my commodore with a 3.8L buick motor when all the antifreeze leaked out on the interstate without my knowing. I plugged the hole filled it with water after a long walk and it was fine.

If you use an e-fan on the trail, make sure it is off when you submerge it in water or you will blow the fuse.

 

[tweakedlogic]

As far as the e-fan on the trail goes, as long as you ahve a kill switch for water crossings it will do fine.

to test your fan clutch, warm up the motor fully, then turn it off and spin the fan by hand. if there is resistance, it's good, if it spins too easily = bad.

 

[The Breeze]

I would look to see if some wires arnt getting burnt. I know that seems silly but I had a friend with a F150 with aftermarket headers when he bought the truck and they fried is starter and alternator wires. Its just a thought.

 

[acschilling]

Update: fuel pressure test showed 10 psi...changed the pump and all seems well. thanks everyone! Kill thread.