White smoke on startup

Jun 18, 2024
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I occasionally have white smoke when the car first starts. I have taken the car to the dealer four times and they cannot tell me what’s wrong. Has anybody had the same problem? Thanks in advance.
Ken is correct. Have them perform a cylinder leak down test. And test the coolant for potassium...
Yes, the white smoke apears when a headgasket starts to fail. Antifreeze coolant leaks into the combustion chamber and burns. Combustion gases may also mix into the cooling system and cause a boil over. If the dipstick becomes a foamy, slimy mess than it is will be conclusive. Look for oil in the coolant.
How many miles are on the car and engine? Lou has the right idea. A cylinder leak down test and/or a compression check usually determines which cylinder is leaking. The Subaru is a boxer engine, so there are two headgaskets, Usually, once the headgasket has blown, it will be time to do a valve grind and replace the valve seals, too.
If you have a head gasket leak, you will be losing coolant. But white smoke can also simply be water vapor condensing in the exhaust system over night as things cool down. On start up in the morning, this condensation will turn into steam, aka white vapor for a minute or two. This is common in humid environments.

But if you are losing coolant, then the head gasket may be on the way out. IF you catch this early enough, and by early enough I mean you are losing less than a cup of coolant a week, you might put off the total failure by having your dealer put in a bottle of Subaru Cooling System Conditioner. This will seal up very minor leaks and will not harm your cooling system like those "Head Gasket" repair bottles.

BTW, I am working on a Nissan engine where my son tried one of those head gasket repair in a bottle solutions. It did over a $1000 in damage to the engine. But the Subaru Cooling System Conditioner is NOT a head gasket repair and is even put into the cooling system of their new cars. It will not fix a blown head gasket. But it does extend the life of the head gaskets IF you use it early enough.

You can get it at Amazon and put it in yourself. I have saved two engines so far with this, but you gotta catch it early.

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