Causes of engine oil consumption: a detailed list

The engine is the car's "heart", and how well it runs is largely determined by the consumption of the oil inside it. There are many reasons for engine oil consumption, ranging from a simple leak to burning.

Oil leaks. If oil is leaking from the engine, the gaskets and seals need replacing. That can mean the valve cover gasket, the cylinder head gasket, the camshaft and crankshaft seals, the oil pan gasket, the rear crankshaft seal, and the gasket under the oil filter. Experienced mechanics use their own tools that let them cut the engine repair time down.

Oil burning. Diagnosing oil burning is fairly easy, since burning good-quality petrol can't produce black smoke from the exhaust pipe. When oil burns, it leaves oily black soot at the exhaust pipe. It's harder to pin down the cause of the burning without opening up the engine. Engine oil can't help but burn off to some degree, since it constantly coats the working inner surface of the cylinders, where the petrol ignites. Oil consumption depends directly on the load placed on the engine: the higher the engine's temperature, the more oil burns off.

Before sending your car off for an overhaul, you need to work out the engine's design features and how it's been driven.

For instance, in a V-shaped engine, oil burns off more intensively than in an inline engine. You can look up the design features of particular carmakers' engines through specialised firms, for whom online advertising is a way of getting their products known.

Causes behind higher oil consumption:

• an engine oil with the wrong viscosity for the car;
• worn valve stem seals;
• worn oil control piston rings;
• damage to the inner surfaces of the cylinders;
• a failed turbo (compressor), or excessive crankcase gas pressure.