Oil level too high or too low — what does it mean?

How to measure correctly

• Park on level ground with a warm engine, then wait five minutes for the oil to drain back to the sump.
• Pull the dipstick, wipe it, push it fully back in and pull it out again.
• The level should be between min and max; the difference is often about one litre.

Many newer cars no longer have a dipstick. The level is shown in the dashboard menu and only reads correctly after driving or standing for a while.

Too low: consumption or a leak

If the level drops, the oil goes one of two ways: burning or leaking. Burning comes from worn piston rings or valve stem seals, or a turbo passing oil — sometimes with bluish smoke on start-up. Leaks show as spots under the car or oil on the engine, often at the sump gasket, rocker cover gasket or shaft seals.

Too high: also harmful

Too much oil can be whipped into foam by the crankshaft, and foam lubricates poorly. It raises pressure on seals and can reach the intake, turbo and catalytic converter through the crankcase breather. If too much was added, have the excess drained.

If the level rises by itself, something is in the oil that shouldn't be: on diesels with a particulate filter often fuel (from many interrupted regenerations on short trips), rarely coolant. The latter is serious — milky oil or a falling coolant level are the signs.

Frequently asked questions

How much oil does a normal engine use?

It varies by engine. If you need to top up more than a litre between services, have the cause found.

I overfilled it. Can I drive like this?

A little above max is no disaster. If the level is clearly above it, have the excess drained first.

The level is rising on my diesel. What now?

There is probably diesel in the oil. Have the oil changed and the particulate filter and regeneration checked.

Work out the price of fresh oil for your engine in the service calculator or read more about the oil change in Tilburg.