Car running hot
I have a 2008 impala, car started running hot 6 months
ago for the first time, changed the radiator cap and it
hasn't done it since. But today it did it again, put coolant
in the resovoir and it was fine, then started running hot
again when I turn in the heater it cools down a little. Don't
see any fluids leaking from bottom...Fans are coming on
any suggestions