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Volucris

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Volucris Enthusiast

Volucris

Posted
Posted

So I'm chugging up a pretty severe 4WD road in 4LO. The coolant temp was up to 225 degrees, and the tranny temp was up to 218 degrees. The electric fan for the radiator never came on. When are they supposed too?

Stevens03 Senior Enthusiast

Stevens03

Posted
Posted

I think the fans start to spin up at around 160... then full speed around 180-190. If you have them, you could have the temps lowered if necessary by a custom tune. I think those temps are a little high. I've never seen mine over 210 on the gauge and never over 180 on the trans. :lol:

 

If your still in warranty, I'd take it in.

bill190 Enthusiast

bill190

Posted
Posted

On older vehicles the fan should turn on when the *computer* coolant temperature sensor is above 225 deg. F. Or when the A/C is on and the high pressure side reaches a certain pressure.

 

For your vehicle, this information would be in a GM factory service manual for your year/model vehicle.

 

And probably you would just test the computer's coolant temperature sensor to be sure it was giving the correct reading for various temperatures. This tells the computer what temperature the engine is. Then the computer decides when to turn on the fan.

 

Also you would want to check fuses. This information would be in your owner's manual. Here is how to check fuses...

http://www.dinosaurelectronics.com/Test_Fuse.htm

 

Then there is probably a relay for the fan and this would be computer controlled. A GM dealer could hook up an electronic tester and tell the computer to turn on the fan. Then you could see if the relay and fan were working when the computer told it to turn on. This would be the best test of the entire fan circuit.

2005LT Enthusiast

2005LT

Posted
Posted

John, are you sure they didn't come on? Did you get out and listen for them or pop the hood and seem them going? On mine I can hear the fans lightly before it even gets up to operating temp (sticks right at 210 on the needle and stays there once warm). Fans run constantly when it's idling and warmed up as far as I can tell.

Volucris Enthusiast

Volucris

Posted
  • Author
Posted
John, are you sure they didn't come on?

 

I'm pretty sure. I stopped once on the way up, popped the hood and took a look. Neither one was running. On the other hand, 225 was where it stopped. There was no reason for it not to get hotter, other than the fans were running.

rogerf Enthusiast

rogerf

Posted
Posted
John, are you sure they didn't come on?

 

I'm pretty sure. I stopped once on the way up, popped the hood and took a look. Neither one was running. On the other hand, 225 was where it stopped. There was no reason for it not to get hotter, other than the fans were running.

 

So you were pulling enough weight up a steep enough grade to need to be in 4-LO? Would not be surprised to see 225 water & tranny temps.

2k8Vmax Enthusiast

2k8Vmax

Posted
Posted

I've had mine get up to about 240-245ish while towing a 17ft. trailer up hill... after that it seams like the fans kicked on at odd temps... i've heard them kick on when temps hit about 230-235. i took it to the dealer and they thought maybe it was the thermostat so they replaced that but that didn't really seam to fix it. they said the fans are set to kick on at 230, and that they were working fine. it usually runs at 210, but it will go up to 225-230 quite often and then drop back down pretty quick. it seams fine when i first start driving but after about 15-20 mins of driving is when the temps start to fluxuate between 210-235ish. ohh yeah... this even happens while driving on flat freeways at about 65-70mph.

I think i'll try another dealer some time this week... i'll repost after i take it in... maybe we are having the same problem..

bill190 Enthusiast

bill190

Posted
Posted

Also on my truck at least, there are two separate temperature sensors. One for the computer, and another for the instrument cluster temp gauge.

 

In the past on various vehicles, I have had these not read the correct temperature (then replaced it), so I would not be surprised if one sensor was reading a bit different from the other.

 

I don't know about your specific truck though. Might ask at the dealer if there are two sensors or one for both functions????

 

Anyone here know?

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