Fans only turn on with a/c on

Discussion on Air Conditioning/Heat & electronic controls for the same, radiators/fans/engine cooling and related items.
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FrogDro
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Joined: Sat Feb 04, 2023 2:09 am

Fans only turn on with a/c on

Post by FrogDro »

Has anyone had an issue where fans only turn on with a/c on? I noticed during wot they’ll turn on as well then stop. I replaced the thermostat because I kept getting weird fluctuations in temperature. Didn’t help I thought maybe air pocket trapped in system so I let it idle with the cap off and noticed without a/c car will get to 220 temp and bubble out the coolant out the tank. With a/c in car keeps its temp… Any ideas?
JoeR
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Joined: Wed May 25, 2022 12:34 am
Location: Central, NC

Re: Fans only turn on with a/c on

Post by JoeR »

What year car? Fan control changed drastically from -2013 to 2014-.
Joe
FrogDro
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Joined: Sat Feb 04, 2023 2:09 am

Re: Fans only turn on with a/c on

Post by FrogDro »

Oof, 2016 sorry thought I had included it
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elc32955
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Re: Fans only turn on with a/c on

Post by elc32955 »

Did you get the checks done that I had recommended to you in the other thread on Feb 6? If so what were the results?

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Eric
System Manager and your tour guide for the day. 2015 Caprice w/LFX, former NC DPS staff car. Partial hybrid G8/SS/Camaro SS interior mods, SS MyLink radio upgrade, 2016 Camaro V6 rims, GMPP Malibu chrome exhaust tips, otherwise bone stock for now.
Sanford
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Re: Fans only turn on with a/c on

Post by Sanford »

If you are running the car with the radiator cap off, there is a good chance it will burp out some antifreeze. The boiling point of a proper 50/50 mix of Dexcool is around 225F. The turn on temperature for the fan is probably in the 220F range. With the cap on, the boiling point is around 265F with 15 psi on the cooling system. Does the temperature go above 220F with the AC off?
JoeR
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Joined: Wed May 25, 2022 12:34 am
Location: Central, NC

Re: Fans only turn on with a/c on

Post by JoeR »

On a 2016 the fans start to run at 220f. Put the cap on and run it. It is VERY unlikely that the pcm will turn the fans on for AC but not when the engine warms up. There is only one fan controller, so there's not multiple failure points.
Joe
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