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Overheating at red lights

Nixons

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Nixons New Member

Nixons

Posted
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I have a 2011 chevy silverado 1500 4.8

I am having a weird overheating issue only at Red Lights.

I'm thinking it's the cooling fans not functioning correctly but wanted to see if you guys had any issues that are similar.

Once I start driving cools right down.

 

Any advice would be apperciated!

2017HD Enthusiast

2017HD

Posted
Posted

Sounds like you have a problem with the thermostat that engages the fan. I believe that on most trucks they still have a real fan on the front of the engine (not electric fans on the radiator) These fans have a thermostatically controlled clutch that engages when the radiator temp gets too high. Otherwise the fan freewheels - you can test this by turning the fan with the engine off - it should move freely. Prior to the clutch the fan blades changed pitch with the RPM of the engine - so at idle they were pulling maximum air and flattened out with RPM so as to pull less.

 

I presume that you have checked your coolant levels etc.

Nixons New Member

Nixons

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  • Author
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I have 2 dual electric fans.

No fan clutch, no manually driven fan off the belt.

They kick on. I'm wondering if there is a relay or something like that I should be addressing.

Yes coolant levels are fine.

Nixons New Member

Nixons

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  • Author
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Driving highway, no heating issues at all. But if you sit at a red light for more than 45 seconds the temp a ture will rapidly rise from 210- any where from 220-240. And then when you start driving it cools down.

arcasey Enthusiast

arcasey

Posted
Posted

Those fans should be controlled by an Engine Coolant Temperature Sensor that communicates with the PCM. There is also a one or two fan relays with fuses if I remember correctly. If they are coming on then there should be nothing wrong with the fans. The issue would be with what tells them to come on. I would also check the engine coolant thermostat also. They are cheap enough that if your fans are operating I would just replace the thermostat to eliminate that from being the culprit. If you want you can check to make sure the thermostat is operating correctly by placing in a pot of hot water on a stove top. Youtube can show you how to verify that a thermostat is working correctly.

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