On a rebuilt engine with relatively low mileage, oil leakage past the valve guide seals is a more likely cause of oil consumption than leakage past piston rings.

Question

Quizplus · Accepted Answer

Valve guide seals are meant to prevent oil from leaking past the valves and into the combustion chamber, whereas piston rings are meant to prevent oil from leaking past the pistons and into the combustion chamber. If oil is leaking past the valve guide seals, it can cause oil consumption without necessarily allowing oil to enter the combustion chamber. Therefore, on a rebuilt engine with relatively low mileage, oil leakage past the valve guide seals is a more likely cause of oil consumption than leakage past piston rings.

On a Rebuilt Engine with Relatively Low Mileage, Oil Leakage