1999 Mazda Protege smoke

MEL POPPE

MEMBER
1999 MAZDA PROTEGE
4 CYL
2WD
AUTOMATIC
540,000 MILES

When I anitially start the car when it is cold outside white smoke comes from the exhaust pipe for 1 minute. After a few popping sounds it stops. In the winter I plug the car in and it doesn't happen. When the day is warm it doesn't happen either.
Mel Poppe

1 Reply

CARADIODOC

MECHANIC
33,871 POSTS

Hi Mel, welcome to the forum. White smoke is a sign of coolant getting into the combustion chamber, usually through a leaking head gasket. Temperature can be a contributing factor because the cylinder head is made from aluminum which expands and contracts a lot as its temperature changes.

A radiator pressure test might help locate which cylinder is leaking too. As the coolant cools down after you stop the engine, the head gasket apparently isn't leaking yet while the engine is still warm. Once everything cools down to where the aluminum head moves or warps and the gasket starts to leak, the pressure is gone from the coolant so just a little dribbles into the cylinder. As the engine warms up, the heads moves and seals before the coolant has time to build pressure.

It is possible for this to go on for a long time, but generally the leak will get progressively worse. Keep an eye on the coolant level in the overflow reservoir. If it gets low enough that it no longer circulates, the engine will overheat which will lead to more head warpage and a deteriorated gasket.

Caradiodoc