what makes engines burn oil?

[paui]

what makes engines burn oil?
is it oil sneaking past the piston rings?

[JeffD]

Yes.

[tkm433]

It depends on the age of the motor.  As you motor racks up more miles the piston rings and cylinder ways will begin to wear and allow for oil "blow-by" to occur.  Usually at this point you will notice a decrease in perfomance since you are no longer getting as good of a combustion chaber seal due to the won parts.  The fix is to usually replace the pistons and rings with new ones and have the cylinders bored and honedto fit the new pistons.  Sometines you can just replace the rings and have the cylinders honed.

Also there is the issue of the valve stem seals beginning to wear out which will also cause the motor to burn oil but usually does not have an issue on engine compression and thus not a s much of a noticable decrease in power from the motor.  Usually bad seals will tend to casue the plugs to foul up with oil.


I guess you were taking about a GS500 or a 4-stroke motor because a 2-stroke motor is a total-loss lubication system in that it mixes it fuel and oil and burns it all thus the smoke from a 2-stroke motor.