Here are some possible causes of oil in the air cleaner:
- Worn piston rings: Worn piston rings can allow oil to leak into the combustion chamber, which can then be blown into the air cleaner.
- Damaged valve seals: Damaged valve seals can also allow oil to leak into the combustion chamber.
- Leaking head gasket: A leaking head gasket can allow oil to leak into the coolant, which can then be drawn into the air cleaner through the PCV system.
- Clogged PCV valve: A clogged PCV valve can prevent the crankcase from properly venting, which can cause oil to be pushed into the air cleaner.
If you find oil in the air cleaner of your 1979 Bonneville, it is important to identify and correct the underlying problem to prevent further damage to your engine.
