Here it is, I have a 2006 Chevy Silverado, 4.8L, V8, and it has been overheating when it sits running. When you drive it cools right down. I have some theories, but I thought I would give Yahoo Answers a crack at it before I fix it this weekend.
Theory 1 is the fan is not running when it is supposed to, ie the thermostat for the fan is bad. You can hear the fan run, but it doesn't cool the truck. I have not cracked the hood yet to see if the fan is spinning, or the fan motor is running but not spinning the fan, ie fan clutch.
Theory 2 is the thermostat is bad, and sticks when the water pressure goes down because the water pump is not spinning fast enough.
Theory 3 is a bad water pump, but I don't think so.
I will probably be able to fix it with no problem, but I thought I would put this out there for you guys and gals to solve. 10 points to the best answer!
Theory 1 is the fan is not running when it is supposed to, ie the thermostat for the fan is bad. You can hear the fan run, but it doesn't cool the truck. I have not cracked the hood yet to see if the fan is spinning, or the fan motor is running but not spinning the fan, ie fan clutch.
Theory 2 is the thermostat is bad, and sticks when the water pressure goes down because the water pump is not spinning fast enough.
Theory 3 is a bad water pump, but I don't think so.
I will probably be able to fix it with no problem, but I thought I would put this out there for you guys and gals to solve. 10 points to the best answer!