We’re used to our cars running well most of the time. Reasonably well maintained, most cars will perform reliably and satisfactorily. So it’s usually quite easy to tell when something going wrong – there’s probably an unusual noise, like a squeak, rattle or roar, that you don’t normally hear.
Or maybe it just doesn’t feel right: the steering isn’t quite as it should be or the suspension is lumpier than you’d expect. Perhaps there’s a vibration running through the car, or a low-down thrum that you have never experienced before.
These situations, where we are using our senses to detect that all is not well with our car, are not particularly unusual. So how about when we use another of our senses – smell – to help us decide if our car needs some attention?
When we think of smells associated with cars, it’s often ‘that new-car smell’, or other familiar smells like leather, plastic, polish or air freshener. But there are certain smells that you don’t expect to notice, and these should get your attention.
The ventilation system on your car should ensure a constant supply of fresh air into the cabin at all times. That means it’s normal to pick up different smells from around your vehicle as you drive, but these should then disappear again just as quickly. If you notice a smell that doesn’t go away immediately, it may be an indication of a problem that you need to sort out.
What sort of car smells should I be aware of?
Here are ten significant scents that could mean trouble. If you notice any of these smells from your car, you should – at the very least – get it inspected.
I can smell petrol or diesel
Let’s start with an obvious one. It’s not unusual to have a little fuel residue on your fingers or the bottom of your shoes after you have just filled up. But if the smell doesn’t go away soon, it could be a more serious problem, such as a fuel leak.
Fuel could be leaking directly from the fuel tank or from somewhere in the system such as the fuel lines which carry fuel from the tank to the engine. Petrol, in particular, is highly flammable so if you can smell fuel from your car then you should get it checked out immediately.
I can smell hot or burning oil
Oil is a critical fluid for your car’s engine, keeping everything properly lubricated and working efficiently. But if you can smell hot oil, it probably means some is escaping through a leak and settling on a hot part of the engine or exhaust system.
Check your dipstick for an oil level indication and look under the car to see if there are any patches of dropped oil on the road or driveway. Have the problem fixed soon – if your engine runs out of oil, it can cause a lot of damage.
I can smell burnt rubber
It’s a pungent whiff and quite unmissable. Assuming that you haven’t been doing burnouts or otherwise spinning up your tyres, the smell of burning rubber could signify that an engine belt is slipping somewhere and getting hot. Or it might mean a hose has worked loose and is touching a moving part such as a pulley, or any part of the engine that gets hot.
Loose belts and hoses will not tighten up again on their own, so have the car seen to.
I can smell exhaust fumes
There are few things worse than a noseful of exhaust fumes – and they’re highly toxic, too. Modern cars shouldn’t emit any really noticeable smell from the exhaust system into the cabin, so if you smell exhaust gas in your car for any length of time you might well have a broken exhaust pipe or other leak in the exhaust system.
As well as the unpleasant odour, exhaust gases can make you feel tired while driving and, if prolonged, can create more lasting health problems. Have the system checked by an expert.
I smell something sickly sweet
Don’t ever think about drinking it, but engine coolant fluid can give off quite a sweet smell. If you start getting unexpected syrupy whiffs coming through the cabin, your car could have developed a leak in its cooling system.
Ignoring this could lead to an overheated engine, which is a costly problem to put right. Get it seen to ASAP.
I smell burning carpet
The smell of burnt carpet is likely to be your brakes (assuming your interior carpet isn’t on fire!). Perhaps something has become misaligned or broken, and your brake pads are dragging. Brakes are obviously an important part of your car’s safety, so you should investigate at once.
Smelling it during or after repeated hard braking – like on a windy, downhill road – is one thing, but it’s potentially a worry if this smell is evident during normal driving.
I smell rotten eggs
This sulphurous pong is probably from the catalytic converter, which is a device in your car’s exhaust system that converts harmful exhaust substances into less damaging ones. A rotten egg smell from your car is not just unpleasant, it can also be dangerous for you and your passengers if unchecked.
If it’s not the ‘cat’, then check the general running of the engine, including fuel filter. It could possibly be leaking transmission fluid.
I smell burning fur
If it’s cold and wet outside, it’s quite common for small, furry animals to take refuge in the shelter of a car’s engine bay overnight – especially if the engine is still warm from you driving home. When you jump in your car the next morning and drive off, they may not have time to get out again. A dead animal smell is unmistakable.
If your car isn’t used on a regular basis, it’s also possible that animals may use your engine bay to set up a new home. Nesting materials, such as straw and dried grass, are a fire risk in a hot engine bay, while the rodents could also start chewing away at your wiring or hoses.
I smell burning plastic
There are plenty of plastic components under the bonnet of a modern car and, if they’re kept away from high heat, there’s no problem. But if they end up touching something hot, they could start to melt and smoke. That produces an acrid smell which should not be ignored.
I smell stale air
We all need fresh air when we drive. If your car’s interior is getting musty, it could be the result of a clogged cabin air filter or perhaps the filters within the air conditioning system.
Clogged A/C units can start to accumulate moisture, which then turns to mould. These spores are not good to breathe in, so have your air conditioning looked at from time to time.
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