hi guys need some help
my gf has a 2004 mazda 6 and she started to have problems with it... it trowing out white smoke out the exhaust (a lot). it has 100,000 miles and the check engine light on. i was going to start with giving the car a tune up ( spark plugs, wires, intake filter, maybe the O2 sensors) what else should i do? clean the injectors? thanks

 

White smoke means coolant burning in the combustion chamber....Most likely you need a new head gasket.

 

i just had a white smoke on starup & while accelerating mazda 6 3.0l that had bad valve guide seals. i had to remove the cylinder heads & inspect the entire motor. all i found was # 2 & # 5 exhast valve seals leaking but we replaced all of them since we were there. the car has not had any problems since.
i have not seen any head gasket problems with the 3.0l yet. but to pull the heads of & inspect the valves you typically have to remove the heads which means the head gaskets are going to be replaced.

 

If the CEL is on as you stated, why don't you take it to a shop & have the code pulled instead of throwing money & parts at the car that will probably not fix the problem.