Smoke From Under The Bonnet
Grey or blue smoke from the engine bay is usually oil or fluid burning on hot parts; dense smoke with a plastic smell can mean an electrical fire. Steam is white and smells sweet.
Critical risk
Stop, switch off the engine and get out. If you see flames, move away and call emergency services.
Short answer · What should I do if smoke comes from the engine bay?
Stop safely, switch off the engine and get everyone out. Do not open the bonnet wide if you suspect fire, because fresh air feeds flames. Light smoke from oil dripping on the exhaust is common after an oil change spill, but it must still be checked. White steam with a sweet smell is coolant, which is a different problem.
Safe checks you can do
- Stop and get outSwitch off the engine and move people away from the car.If there are flames, call emergency services and stay away.
- Identify the smellOil: acrid; plastic or rubber: electrical or belt; sweet: coolant.
- Look for leaks once coolOil on the exhaust manifold is a common source.
Questions that narrow it down
- Was the oil just changed?Spilled oil burning off.
- Plastic smell?Electrical fault; dangerous.
- Is the temperature high?Overheating.
Possible causes
Listed without ranking. Use the questions above to see which ones fit your car.
- Oil leak onto exhaustValve cover gasket and similar.
- Spilled oil after a serviceBurns off briefly.
- Electrical shortMelting insulation.
- Slipping beltRubber smell and smoke.
- Coolant leakWhite steam, sweet smell.
Questions about Smoke From Under The Bonnet
Is a little smoke after an oil change normal?
A small amount from spilled oil can be, and it should stop quickly.
Should I use a fire extinguisher?
Only if it is safe and you know how; your safety comes first.