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2011 1500 Sierra w/t overheating at idle or slow speeds


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So, I have a 2011 Sierra half ton, it’s overheating at idle in gear. In park it won’t. Soon as you start moving it cools off, the fans do turn on but they don’t seem to turn on fast enough. It’s already starting to overheat by the time the e fans kick on. Soon as you start moving, cools right off instantly. This tells me maybe sticky t stat? Maybe coolant temp sensor? What temp are the fans supposed to kick on? Thoughts...tia

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Define hot?

 

What is the temp gauge reading and what is the computer saying? A handheld scanner reported a different value than the cluster pretty much every time.

 

The fan temps aren't exactly broken down by temp, once triggered to come on it's a desired fan percent based on temp. It's roughly 50% fan between 210-220 and then it requests full speed from 228-250 degrees. If the A/C is on, one fan should always be working.

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1 hour ago, CamGTP said:

Define hot?

 

What is the temp gauge reading and what is the computer saying? A handheld scanner reported a different value than the cluster pretty much every time.

 

The fan temps aren't exactly broken down by temp, once triggered to come on it's a desired fan percent based on temp. It's roughly 50% fan between 210-220 and then it requests full speed from 228-250 degrees. If the A/C is on, one fan should always be working.

I’ll check tomorrow with my hand held I’ll report back. I soaked rad cap in soapy water for a bit too, it will only go above the 100* mark on the gauge cluster if you put in drive and hold the break at idle for awhile, fans DO kick on but only when at about 106* roughly on the cluster. Which is not normal for this truckit would never rise above 100. Soon as fans kick on or you turn AC on it cools off instantly..

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