My car emits a big puff of blue smoke on startup after sitting a while . Whats wrong?

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  • Anonymous
    1 decade ago
    Favorite Answer

    OIL IS LEAKING PAST THE VALVE SEALS AND ACUMULIATING IN THE CYLINDER THEN WHEN YOU START IT IT BURNS IT ALL OUT QUICKLY BUT THE VALVES DON'T LEAK ENOUGH FOR YOU TO NOTICE WHEN THE ENGINE IS RUNNING...AS SOON AS YOU SHUT IT OFF THOUGH, DRIP,DRIP,DRIP

  • 1 decade ago

    Valve seals are worn. When the engine sits for a while, the worn valve seals allow oil to pass the seals and run into the combustion chamber. When you start the engine, this oil burns and you get the puff of blue smoke.

    If your car is worth the expense, have the cylinder heads rebuilt. But depending on the make of your car, this could cost well over $1000. Foreign makes will generally cost twice as much to have this repaired as domestic makes. Add even more for DOHC and 4 valve heads.

    If it's an older car, I wouldn't spend the money.

  • 1 decade ago

    Sounds like you have a bad valve guide or bad valve seal. You don't mention the vehicle, but I do know this is common for the Ford 4.0L V6 after 50K miles.

    Stop by a reputable shop and ask them the price on a valve job. Then ask them the price to verify the diagnosis, before making the repair.

  • Anonymous
    1 decade ago

    Probably the vavle seals. No big deal. Normal for most Dodge and General Motors cars.

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  • 1 decade ago

    i have seen some diesel's do that;)...if oil is leaking past your pistons into your combustion chambers your having a loss of power and a loss of oil..the rings aren't making contact with the pistol walls if thats the issue... if you consistently see blue smoke take it to a shop and get it checked out.

  • 1 decade ago

    The most likely causes are worn valve stem seals or worn piston rings. Or both.

  • 1 decade ago

    If your car is old it could be a mixture of gas that hasn't been burnt if your car is carbureted instead of EFI.

  • 1 decade ago

    this indicate your engine is leaking oil internal. if you don"t fix,more damage will occur or worst,you will get a traffic ticket for polluting the air

  • 1 decade ago

    valve seals...common on ALL cars, unlike what what was answered earlier.

  • 1 decade ago

    It's old. Unless you notice any other driveability issues, it's probably okay.

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