Hello, newbie RC car guy,
Recently fitted a new ESC and motor to my car, also using a 3S Lipo battery. however my new ESC comes with a fan on top. as soon as I flick the power switch the fan spins up like its trying to make the damn thing fly.

Is this right or have i done something wrong?
Many thanks.

I am sorry to say that is very common especially with cheaper escs. Alot of fans on escs are really rated for max 2s lipo they usually say this in the manual. The fan is being run from the voltage of the battery and is not regulated by the esc so the stronger the battery the faster the fan spins. Some escs you can get away with it but run the risk of burning out the fan. The safest way to me is get a fan rated at 5v and run it off the receiver so it gets consistent power no matter what battery you use.