Sounds like a rebiuld time.
I don't know what moter U have,, but on our JLG 600A at work we have had a problem with the Ford duel fuel engings blowing the #3 cly oil ring wich would cause the oil from the crank case to blow in to the intake do to the fact the PCV is monted on the block
and it would run bad/smoke and over heat <not that they don't run hot as it is)
