Exhaust fumes smell in the car: why it matters

Smelling exhaust fumes inside your car is not something to put up with. Exhaust gas contains carbon monoxide, which has no smell of its own and can make you drowsy, give you a headache or cause nausea. If you can smell fumes in the cabin, open the windows, avoid long drives and arrange a proper check.

This guide covers where the smell usually comes from, what you can do while waiting for an appointment, and how a garage tracks down and cures the leak.

What should I do if I smell exhaust fumes in my car?

Ventilate straight away by opening the windows and switching the heater to fresh air rather than recirculation. If you feel dizzy, sleepy, sick or get a headache, pull over somewhere safe, get out into fresh air and seek medical advice if symptoms continue. Do not carry on driving with symptoms.

Avoid sitting in a stationary car with the engine running, especially in a garage or an enclosed space. Then arrange for the vehicle to be inspected before further regular use.

Why do I smell exhaust inside the car when stopped or moving?

Fumes usually enter the cabin through gaps. A leaking exhaust joint, cracked manifold, failed gasket or rusted section of pipe lets gas escape beneath the car, and in some conditions it is drawn up through holes in the floor, a worn boot seal or gaps around grommets.

The smell can be worse when stationary in traffic, going uphill, or with the boot open on certain estates and hatchbacks because of the way air flows around the body. Where the smell is strongest gives useful clues.

• Corroded or cracked exhaust pipe sections
• Blown gasket at the manifold or a joint
• Damaged flexible section
• Worn rubber seals around the boot or tailgate
• Holes or gaps in the floor or bulkhead grommets

Could it be something other than the exhaust?

Sometimes. A rich-running engine can smell strongly of fuel, burning oil can give a sharper smell, and a heater problem can bring in sweet or damp odours. A smell of fuel is a fire risk and needs prompt attention, as does any burning smell with smoke.

Because several faults can seem alike, it helps to tell us whether the smell is like raw fuel, sooty or sulphur-like, and when it appears. A visual inspection and a check of the engine management system often separate these causes.

How does a garage find and repair an exhaust leak?

With the car on a ramp and the exhaust cold, a technician checks the full system from manifold to tailpipe, looking for soot trails, holes and loose joints. They also look at seals and other routes for gas to enter the cabin. Sometimes the engine is run to listen for a blow.

The repair may be as simple as replacing a gasket or clamp, or it may involve replacing a corroded section. Costs depend on which part has failed, how corroded the fixings are, whether it comes as a section or complete system for your vehicle and the labour time. We will not promise a fix before looking at the car.

Is it safe to drive to the garage with fumes in the cabin?

If the smell is faint and you have no symptoms, short journeys with the windows open are sometimes reasonable to reach a garage, but it is not worth taking risks. If the smell is strong, if you feel unwell or if there is smoke, do not drive.

Our garage at Longcombe Cross near Totnes can inspect your exhaust system and tell you what is causing the problem. If you are unsure about driving the car, ask for advice when you contact us.