Oil pressure warning light: stop the car now

What the warning actually means

The symbol looks like an old-style oil can, often with a drop falling from it. It warns about low oil pressure, not simply low oil. Being low on oil can be the cause, but pressure is what the light actually measures.

How engine oil protects the engine

Engine oil keeps a thin film between metal parts that move against each other, such as the crankshaft, the pistons and the camshaft. The oil pump pushes the oil round the engine under pressure, so that film is there the whole time the engine runs.

When the pressure drops, the moving parts are no longer properly lubricated and metal starts to wear against metal. That is why the damage can happen within minutes, and why this light is red.

Common causes

• Low engine oil level
• An oil leak
• A failing oil pump
• A faulty pressure sensor, giving a false warning

What to do now

1. Pull over safely and switch the engine off.
2. Wait several minutes on level ground, then check the dipstick.
3. Top up with the correct oil only if the level is below minimum.
4. If the warning remains on, switch off immediately and arrange recovery.

What people often get wrong

That the light means "low on oil". It measures pressure, not level. A car can show enough oil on the dipstick and still have lost pressure, and that is just as serious.

When the car must go to a workshop

If the light stays on after topping up, or you are unsure, the car should be towed. Driving on without oil pressure can cause serious engine damage within minutes.

Read next

• Battery light on while driving: what it means
• Brake warning light: check this first
• Your check engine light isn't random
• How to check your engine oil, and what the dipstick tells you

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.