i was workin on my car the other day getting ready for winter and i noticed when i had it at idle the fan would switch on and off randomly. is that normal cuz i never seen a car do that or is my relay bad or some thing ??

 

What happens is that as the car is warming up, 1 the thermostat is closed as to not circulate coolant and until the coolant reaches a certain temp and than the thermostat will open allowing things to circulate, once the coolant reaches a certain temperature it will kick the temp sensor on, therefore kick on the cooling fans which pull hott air away from the radiator taking heat from the coolant with it,

at idled and once the car is at operating temperatue there should be a decent rythm to the turning on and off of the fans.

 

that sounds right but i still got one question.. the car was a operating temp and the coolant was still cold but the fans still turned on and off and even after the thermostat opened it still did it just not as much. im sure its normal but i was just curious cuz i never seen any other car do that.

 

Shouldn't be a problem... they can come on kind of randomly like that, any time the car's on. The only problem is if they aren't coming on when they need to, so just keep an eye on your temp when you're driving every now and then and make sure it's doing what it's supposed to do when it's supposed to do it.

 

yeh it doesn't over heat or any thing i was just curious why the fan did that. thanks for the help.

 

The thermostat should open when coolant temp reaches 195F. The fans should come on when temp reaches 220F or so, and shut off when they get down to 200F or so. They'll also come on whenever the a/c (including defrost) is on.

Best of luck!