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Will engine oil mixed with gasoline ruin a car motor?

My son was low on gas one day and grabbed 2.5 gallon plastic container holding a mixture of gasoline and oil for the chain saw. Shortly there after the car began running harder and harder back firing etc. until it wouldn't run at all. Our mechanic said there was a leak in the block (I think) and we'd need a new motor.

Is it possible the Oil in the Gasoline mucked up the motor to a point it created a leak in the block?


  • edited December 2010
    No, that is NOT possible..I dispose of two-stroke mix all the time by dumping it into my car and truck..A little "top oil" never hurt anything..
  • edited December 2010
    It may smoke and stutter a little bit, but it won't cause a "leak in the block". That can occur in very cold weather when your antifreeze is too weak, or you blow a head gasket, which may ppear to be a "leak in the block".

    Your son must have done something else to the car or the cold weather and weakantifreeze cracked the block.

    Ask the mechanic to fully explain what happened and where the leak is.

    P.S. I would never put an oil/gas mixture in a modern car; my 1948 Chevy in college, however, used so much oil that it might as well have had a 2 cylce engine.
  • edited December 2010
    I also dispose of my old 2 stroke oil in my car but I have never put 2 1/2 gal in an empty tank, I always do it on a mostly full one so I can't say for sure.
  • edited December 2010
    If the catalytic converter was already marginally plugged the 2-stroke oil may have been enough to finish plugging it and causing a loss in power and possibly back firing. But a couple of gallons of 16 to 1 mix would not directly cause any mechanical damage.
  • edited December 2010
    High quality two-stroke oil uses ashless dispersants that leave no deposits or smoke..It burns very cleanly in a four-stroke engine..When diluted to 200 to one or more, it's not an issue...

    In this case, if the tank was empty or near empty, one has to assume the first stop was a gas station, so again, the chance of damaging the engine is remote or non-existent..
  • edited January 2011
    How do you put the phrases "I think" and "need a new motor" in the same sentence? Get clear with your mechanic on his diagnosis and then get a second opinion.
  • edited January 2011

    I think the two-cycle engine mixture may have at worst fouled your plugs.

    The bottom line is that a little two-cycle engine oil in your gasoline in not going to ruin your engine.
  • edited January 2011
    I doubt very seriously there is a leak in the block and it would be interesting to know how your mechanic arrived at this conclusion.

    You might also clarify "shortly there after" because to some people that can easily means weeks or months.
  • edited January 2011
    Get a 2nd opinion. Mechanics are drama queens sometimes.
This discussion has been closed.