Also check you radiator to see if air passages are clogged. This is a commonly over looked area. Usually they clog with dead bugs or sand and dust kicked up by cars in front of you. Ususlly a good squirt with the hose takes care of most of the filth, you can use a mild cleaner and a brush, but if you do make sure you rinse real good as some detergents will cause the aluminum radiatir to corrode.
