Causes of High Oil Consumption

- Overfilling. If the oil is filled to a level above the recommended maximum level, a large amount of oil is thrown up against the cylinder walls and oil is thrown out through the crankcase ventilation. Do not fill the oil level above the MAX line on the dip stick.

- Oil grade. If an oil grade other than that recommended by Volvo has been used, this can result in increased oil consumption. If the oil is too thin, it will contain a larger proportion of volatile molecules. It becomes even more difficult for the oil to maintain an unbroken film around the cylinder walls at high temperatures, leading to increased engine wear and consequently increased oil consumption.

- Hard driving. Long, continuous driving at high engine revs leads to high oil temperatures, which in turn leads to the oil being thinner and consumption higher. Hard cornering at high engine revs results in the oil being thrown against the side of the cylinder block and against the cylinder walls, leading to increased oil consumption.

The same conditions arise during extended periods of driving at high revs in low gear on level roads (no inclines).

- Driving in mountainous areas. Frequent and extended engine braking heats the oil in the engine; it also results in more oil being sucked into the cylinders because of the high partial vacuum in the intake manifold.

- Idling. If the car is used in city traffic, getting caught in traffic jams etc., the engine can be running for a number of hours without covering much distance. This does not necessarily affect oil consumption, but the measurement result - quarts of oil/road distance covered - will be misleading.

- Climate. In very high temperatures, the engine also runs at a higher temperature, leading to increased oil consumption.

Mechanical causes:

Leaks:
Worn crankshaft and crankshaft seal, external leakage, e.g, leaking gaskets, etc.

Crankcase Ventilation:
Overpressure in the crankcase caused by blocked crankcase ventilation.

Pistons and piston rings:
Worn piston ring grooves. Fatigued, worn, scored, broken or scratched piston rings. Fouled oil control rings. Incorrectly installed rings.

Cylinder walls:
Worn or scored.

Valves:
Worn guides or valve stem. Worn, damaged or valve stem seals missing.

Cylinder head:
Internal leakage between oil ducts and leakage into the combustion chamber.