Car smells that require a service check

Smell coming from your car?

Although all cars have a recommended maintenance schedule, it can sometimes be up to two years between services and mechanical problems do arise in the meantime that should be addressed as a matter of urgency.

Problems of which you become aware – by noticing unusual sounds, a change in the performance of your vehicle or strange smells – should never be ignored as a minor fault could develop into a costly repair or, worse still, place you and your family in danger if left unattended to.

Once the initial new car smell has dissipated, you quickly become accustomed to the normal odours of your car, so should be alarmed by the presence of unfamiliar or suspicious smells that suddenly invade your vehicle. Often these may come from outside, but if they haven’t cleared after a few minutes’ driving, it’s important to seek professional advice about the cause, in case a costly or dangerous fault has developed.

These are some of the most common unwanted smells that may indicate your car needs an immediate service check:

Rotten eggs

Unmistakeable because of the way it smacks you across the face when you open the car door, a smell of rotten eggs is either the result of a dropped hard-boiled down the back of your child’s car seat (although unlikely), or a pooling of hydrogen sulphide in the catalytic converter. Under normal circumstances the catalytic converter should convert hydrogen sulphide into sulphur dioxide, so its failure to do so could be the result of an underperforming engine.

Initially, trying a different fuel brand or grade could help to solve the problem, but a thorough inspection by a garage is recommended, with the complete replacement of the catalytic converter the worst possible solution.

Burnt carpet

A burnt carpet smell could indicate a problem with your car’s brakes and should therefore be investigated as a matter of urgency, as a loss of braking efficiency is clearly to be avoided.

While you would have expected to notice other signs of worn brakes, including squeals or crunching when braking, a burning smell could mean the brake pads have worn completely and are grinding on the brake discs. This will not only quickly damage the discs but will also mean your brakes will work with far less responsiveness that normal.

A similar burning smell can also be created by a slipping clutch, so observe whether there is any loss of traction when travelling up hills, or if the engine revs but fails to respond if you attempt to accelerate quickly at 30mph.

Fuel

Obviously when you’re refuelling your car, you can expect there to be a lingering smell of fuel, especially if you manage to get it on your hands, but away from petrol stations, you shouldn’t ordinarily notice it. A sudden fuel smell in the interior of the car could indicate a leak, for example in the fuel lines.

As there is a very real danger of fire, immediate action should be taken to have the problem thoroughly investigated.

Sickly sweet smells

The distinctive, sweet smell of engine coolant may indicate a leak in the cooling system which, if left untreated, could result in your car grinding to a halt at the roadside and overheating. It’s recommended to let a professional technician investigate the source of the leak as it could be in any one of a number of places, including from hoses, the cylinder head or the radiator. As the cooling system is highly pressurised, it’s likely that a minor leak will rapidly become significantly worse, so don’t ignore it.

Burning oil

A smell of burning oil is a sign that oil is escaping onto the hot engine, most probably from a failed seal or gasket. As a minor leak can worsen, it’s always worth having the problem checked.

An oily smell from the exhaust, especially if accompanied by a slightly blue smoke, is a more worrying sign that the engine that may have seen better days.

Whatever the smell in your car, you’ll know if it’s unusual. Always treat a bad odour as a warning sign of an underlying problem, so that a prompt repair can be carried out quickly and with minimal impact on your wallet or your safety.