Fan Questions

[Chadgervais]

So summer is upon us again, which means the car heats up even faster at idle. I saw it get up to 222* at the end of an offramp today, it was about 85 outside. I know our fans are programmed to kick on at 218 and 228 low and high speeds. Is there a way (other than with a Tech-II) to set the fans to kick on at a more reasonable temp(perhaps 202 and 212)? If a Tech-II is the only way to do it, will a Goodwrench shop actually do this, or will they just look at me crosseyed?


Is the high speed fan setting related to RPM? I notice with the AC on, if the engine is hotter than about 205, its louder than usual when the engine revs up, and the sound falls when i let off the gas.


I know running the AC kicks the fan on automatically, and I know my fans are in proper working order. At a moderate outside temp (70-75 degrees) at highway speed, my car runs between 197 and 200 with the AC off and between 200 and 204 with AC on, which seems normal to me considering the extra load. Today being 85 out, with the AC off I was still running 197-200, but turning the AC on spiked it to 213. A 15 degree outside temperature difference should not have that much of an effect on the cooling system, if it were 105-110 outside, that would be a different story. Is there a problem here or is it just another GM cooling system quirk? Id like to climb Mt Washington this summer, but I just don't trust my cooling system.

Of course, killing the AC and cranking the heat full blast drops me right down to 193-195, but who wants to do that all summer?

[Fivefingerdeathpunch]

The temps you are seeing arent even in the danger zone and are causing no harm to the car. The temps went up very quickly when it no longer had air passing through the the front of the car.

Fan speed is not related to rpms.

A dealership could reflash the computer with different fan settings, but it would cost a pretty penny.

The aeroforce scangauge can also manually turn on fans when ever the drivers wants them on. A custom tune is the other way to change fan settings.


I also see that you have over 230k on the car, have you ever thought about taking the fans out and spraying water through the back of the radiator to clean all the dirt and debris out of the fins.

[Chadgervais]

The temps you are seeing arent even in the danger zone and are causing no harm to the car.

My father always told me "fix a problem before it becomes a problem" I know 220 is not considered overheating, but I also know that when you reach the red zone, you already have a problem. My goal is to stay as far away from the red zone as practicable. Every other (non-GM) I have driven, the gauge never passes the center line, 220 is one notch over, which sets off the warning bells in my head.

My concern today was seeing a 13 degree spike (200 vs 213) when the AC normally adds no more than 4-6 degrees to the engine temp.

As for cleaning out between the fans and radiator, the old owner did that at 180k.