Temperature would fluctuate between 210 mark and almost to the next tick line only at idle?

RJONES91S

MEMBER
2010 CHEVROLET SILVERADO
4.8L
V8
4WD
AUTOMATIC
103,000 MILES

The truck listed above is an LS extended cab. My truck had a small coolant leak from the water pump and the temperature would fluctuate between 210 mark and almost to the next tick line only at idle. Replaced water pump (CarQuest brand) still same result with coolant temperature. Switched out the thermostat for a new one (CarQuest brand) same result with temperature. Plug in scan tool. The engine temperature gets to 224 225 then fans kick on them and will go back down to 210. This only happens at idle. From what I’m reading elsewhere anything above 210 isn’t normal? Wondering if the temperature sensor should be replaced or is it something more expensive?

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
47,690 POSTS

It does sound a little warm, I would make sure both fans are coming on and not just one, also I would use a garden hose to blow out the cooling fins from the front and rear of the radiator.

This guide can help:

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Here are the engine cooling fan wiring diagrams so you can see how the system works and I have included how to change out the cooling fan motors in case one is not working. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

Images (Click to make bigger)