running hot

[Jewel or Jalopy]

I noticed tonight that my coolant temp was creeping up to about 235. I was driving about 30 mph or stopped without a/c. When I turned the a/c on the temp dropped quickly.

Sound like a bad fan clutch? I assume when I turn on the a/c the fan helps cool it down

I was planning a 3 hour trip to the desert on Tuesday, so hope to resolve this Monday

Thanks,
Ian

 

[Rivieraracing]

Unless you have electric fans in your truck, I'd say its weird that the temp went down when you put the AC on!! Might be a thermostat going bad, is this the first time this happened since you've owned your truck and how long did it stay at a higher temp before it went down?

 

[Jewel or Jalopy]

It stayed up above 210 for a few minutes, 5 max. I turned on the A/C, picked up my buddy at the airport, then tried turning it off again and again the temp went up. The second time when I turned on the A/C the temp didn't drop immediately, but did after a few minutes.

Do these trucks have any kind of electric aux fan for when the temp gets high?

Just a week ago we took her down to Detroit Lake towing our trailer, 2 hours both ways, and I never noticed the temp creeping up at all. But we were moving 99% of the time.

I'm going to price out a water pump and fan clutch this morning, I might be doing a waterypumpectomy this afternoon. Fun.

 

[Rivieraracing]

It stayed up above 210 for a few minutes, 5 max. I turned on the A/C, picked up my buddy at the airport, then tried turning it off again and again the temp went up. The second time when I turned on the A/C the temp didn't drop immediately, but did after a few minutes.

Do these trucks have any kind of electric aux fan for when the temp gets high?

Just a week ago we took her down to Detroit Lake towing our trailer, 2 hours both ways, and I never noticed the temp creeping up at all. But we were moving 99% of the time.

I'm going to price out a water pump and fan clutch this morning, I might be doing a waterypumpectomy this afternoon. Fun.

Sounds like fun for sure!! lol Unless your clutch fan had electrical wires going to it, it still makes no sense that your AC trick worked!! Good luck with the minor surgery today, and be sure to replace that thermostat while you are in there!!

 

[Wake]

I noticed tonight that my coolant temp was creeping up to about 235. I was driving about 30 mph or stopped without a/c. When I turned the a/c on the temp dropped quickly.

Sound like a bad fan clutch? I assume when I turn on the a/c the fan helps cool it down

I was planning a 3 hour trip to the desert on Tuesday, so hope to resolve this Monday

Thanks,
Ian

Sounds normal to me.

What was the outside temp today where you are? In slow/stop and go traffic your temps will climb without the A/C on. These trucks should be like other emissions controlled vehicles where they run to about 240 before the fan kicks on (without A/C). The A/C on demands cooling (like your outside home A/C unit) when the compressor is running. So it kicks on the fan before the engine temps rise to 240F.

 

[Jewel or Jalopy]

I picked up a fan clutch at O'Reily's and replaced it this morning, good grief was that an easy job! Probably an hour soup to nuts. The upper radiator hose hardly had any coolant in it, I was expecting a huge mess when I removed it. The clips for the fan shroud actually came apart easily, and the fan clutch came off with a few taps of a hammer on the wrench. For once everything went as it was supposed to. And after replacing the clutch the temps sit just below 210 again.

I still want to replace the water pump, upper and lower hose, and thermostat. But I didn't have time to get to those today. I'm more confident that will be an easier job that I was expecting now.

The A/C was also having trouble recently, and in other threads others had mentioned the correlation between not enough air moving through the radiator at low speeds, and therefore also not cooling the freon. At highway speeds all was good as the fan clutch isn't doing much anyway.

Thanks guys!

 

[Jewel or Jalopy]

Well she's still losing coolant, so I'll be replacing the water pump, t-stat and upper hose tomorrow. I'm hoping it's as easy as the fan clutch was. Will report back.

 

[Wake]

Do you see where it's losing coolant? If the water pump isn't leaking then I wouldnt' replace it yet. If it's not that then it won't stop your coolant loss.