A warning light that means stop
The red oil-can warning light signals insufficient oil pressure – not simply a low oil level. Without pressure, oil can no longer reach the moving parts: big-end and main bearings, camshafts, turbo. A few minutes is all it takes to destroy them.
Red warning light on while driving: pull over somewhere safe as soon as possible and switch off the engine. Do not restart to "see if it clears".Likely causes
- Very low oil level, due to a leak or oil consumption. Check immediately with the engine off for a few minutes, on level ground.
- Faulty oil pump or blocked strainer caused by deposits, often after infrequent oil changes.
- Faulty pressure sensor or oil pressure switch: the least serious cause, but impossible to confirm without measurement.
- Advanced bearing wear: pressure drops mainly when the engine is hot and at idle.
Red warning light or amber warning light?
On some vehicles, an amber warning light indicates only a low oil level: a top-up is needed, but you do not need to stop immediately. The red light, however, signals a pressure fault and requires you to stop. Consult your vehicle's handbook if in doubt.
After checking
If the level was low and the warning light goes out after topping up, have the leak or consumption investigated. If the level is fine and the warning light stays on, have the vehicle towed: a pressure reading with a gauge will determine whether the fault lies with the sensor or the pump. If the engine has been running without pressure and is now knocking, the bearings are damaged – a reconditioned engine sold on an exchange basis, supplied bare and warranted for up to 24 months, is then the solution.
