Cooling fan turns off 2012 Silverado 1500 5.3

Silverado-owner · September 6

Thanks in advance to anyone that helps. I start work early at 5am and I drive all day until 2pm, at around 1pm the temperature starts to going up from the normal 210 all day, then I check the fans and the one on the driver side (I’m guessing it’s the radiator fan) it shuts off, keep in mind I live in Phoenix so it’s been 115f for the past 2 months. I have replaced: thermostat, relays, fuses, water pump, both fans twice because I thought the first set was defective, hoses and last the radiator. As you can imagine I’m out of ideas of what to replace next because from 5am to 1pm both fans and the truck works fine so anything helps, thank you for your time.

2015SSilverado · September 6

8 hours ago, Silverado-owner said:

Thanks in advance to anyone that helps. I start work early at 5am and I drive all day until 2pm, at around 1pm the temperature starts to going up from the normal 210 all day, then I check the fans and the one on the driver side (I’m guessing it’s the radiator fan) it shuts off, keep in mind I live in Phoenix so it’s been 115f for the past 2 months. I have replaced: thermostat, relays, fuses, water pump, both fans twice because I thought the first set was defective, hoses and last the radiator. As you can imagine I’m out of ideas of what to replace next because from 5am to 1pm both fans and the truck works fine so anything helps, thank you for your time.

Wow! That can get expensive. The radiator has two Transmission Fluid lines (One to send hot from the transmission as it goes through then another one to return cooler fluid back to the transmission). If any of the radiator hoses are soft or leaking, then it's time to replace all of them. Coolant reservoir should have a full mark on the outside of the container.

In my 2015 Silverado Crew Cab 5.3L, I had both fans run for 5 minutes (or longer) after turning off the engine. It was fixed by replacing the thermostat (part consists of stout hard plastic hose fitting with a thermostat inside. My first clue was the fan running fast while driving then even after turning off the engine. Look at the temperature gauge which should be straight up in the middle. With your climate, If driving is stop and go, then higher temperature coolant could be normal. Highway driving will send a lot more air over the radiator to remove heat. Check mixture is fresh with 50% antifreeze and 50% distilled water. Be sure the coolant is maintaining pressure (little below 15psi is normal) Too much pressure causes leaks. You should be able to get a pressure test kit (loaner tool) at Pep Boys, Auto Zone, or O'Reilly's to see if system is sound. Does the engine run smooth? Hope this finds you more success.

2015SSilverado · September 6

P.S. There is a temperature sensor near the thermostat. The thermostat and coolant temperature control the fan starting and stopping. I wouldn't rule out that temperature sensor near the thermostat.