Does this occur in the city, at highway speed, or both? Do you hear the electric radiator fan turn on? If it does, the head gasket might be leaking. Your mechanic can test for that by drawing air from the radiator through a glass cylinder with two chambers partially filled with a special dark blue liquid. That liquid will turn bright yellow if combustion gases are present.
Wednesday, June 29th, 2011 AT 7:49 PM