The amount of damage done to an engine as a result of being over-filled with oil will depend on the amount by which it was over-filled.
If excessively overfilled, extensive damage can be done. If the level is too high the piston can splash into the oil causing several problems:
- Aeration of the oil and loss of oil pressure
- Excessive crankshaft pressure, which can cause the oil to be forced out of the engine dipstick hole, oil filler or crankcase ventilation valve
- Excessive oil burning
- Hydraulic lock of the engine causing damage to major components
If you have overfilled your engine, your mechanic or RAC Auto Services will be able to help.