How to check your engine oil, and what the dipstick tells you

Why it matters

Engine oil lubricates the moving parts and carries away heat and contaminants, which is part of why running low on oil is far more serious than it might seem. Oil also breaks down under heat over time, and running an engine on old, dirty oil is one of the most common causes of premature engine wear.

On a turbocharged engine a low level is more serious still. The turbo shaft runs on a thin film of engine oil, and without enough flow its bearings can be damaged very quickly.

What you need

• Level ground, and an engine that is switched off and cold
• A flashlight and a pair of gloves
• The oil grade from your owner's manual, if you need to top up

How to check it, step by step

1. Park on level ground and switch the engine off. Check it cold: almost every fluid level reads wrong on a warm engine or on a slope.
2. Read the level on the dipstick. The oil should sit between the min and max marks.
3. Look at the color and consistency. Translucent brown is what you want to see. Black, sticky oil means the change is overdue.
4. If the level is low, top up with the grade in your owner's manual, to midway between the marks.
5. Write down what you find, so you can tell whether the level drops between changes.
6. Look at the ground where the car is parked. Dark drips are oil.

What the oil on the dipstick tells you

• Between the min and max marks, translucent brown: as it should be.
• Below the marks, or close to the lower one: top up with the correct grade to midway between the marks.
• Darker than new, but the level is fine and the change is not due: normal. Oil darkens with use, so go by the interval in your manual.
• Black and sticky, or very dark and gritty: the oil change is overdue.
• Lower every month between changes: get it checked soon. An engine should not use a meaningful amount of oil between changes.
• The oil pressure light comes on: this is not a level reminder. Pull over, turn the engine off, check the level once it has cooled, and tow it if the light stays on after topping up.

What people get wrong

That dark oil is bad oil. Oil naturally darkens with normal use: the mileage and time on the clock tell you when it is due, not how it looks on the dipstick. Only oil that has turned black and sticky tells you on its own that the change is overdue.

When to leave it to a workshop

Have it checked soon if the level keeps dropping between changes, or if you see blue exhaust smoke, which usually means oil is being burned. If the oil pressure light comes on and stays on after topping up, have the car towed rather than driven.

An electric car has no engine oil to check at all, but a hybrid's petrol engine needs its oil on schedule like any other engine.

Read next

• Oil pressure warning light: stop the car now
• Car burning oil: how to tell and what it means
• Exhaust smoke color: white, blue or black explained

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.