Why does my car heater smell?

by admin | Posted on Thursday, June 30th, 2016

Sometimes in life following your nose is the best option. When it comes to identifying any problems with your vehicle, it’s certainly a good indicator that something might be wrong. But what can a smell really tell you about the welfare of your car? Radiator specialists Advanced Radiators have provided this guide to what’s behind your car heater smell….

Why does my car heater smell

The smell: Petrol

If you smell petrol from your car heater, it could suggest that you have a leak either in your petrol tank, carburettor or fuel injector line. If your fuel pump is visible, check that – if fuel is leaking, you may be able to see a clean streak across it. If you can, check your fuel lines and if you smell petrol from there, you will likely have a leak.

Remember that leaking fuel can present a fire hazard, so finding the source of the leak and getting it fixed should be a top priority. Be careful around the vehicle, and certainly don’t smoke near your car!

The smell: Rotten eggs or sulphur

Not a great smell at the best of times, and certainly not one you want to come from your car heater! The cause of this smell is hydrogen sulphide, which can be found in your car’s fuel. Your catalytic converter is responsible for converting the hydrogen sulphide in the exhaust to sulphur dioxide, so smelling rotten eggs could be a sign that it’s not working correctly. There could also be a problem with the engine, with it overloading the catalytic converter. Get it checked out by a mechanic if the smell is consistent.

The smell: Burning or hot oil

If you can smell burning or hot oil, there’s a chance you could have an oil leak. The oil dropping onto the hot exhaust explains the burning smell and should help you to quickly identify the problem. This will be particularly evident when you drive uphill, which can cause your exhaust to overheat. Tell-tale signs will be smoke coming from the engine or patches of oil on the floor.

The smell: Syrup

For those who haven’t experienced this before, it might be quite surprising to learn that a car can smell of syrup. But if your car heater smells sickly sweet, it could be a sign of your car leaking engine coolant. Engine coolant has a very sweet and oily smell. If you can smell it from your car heater, check for dampness in your car – it could be a sign of leaking in the heater. If you can smell it from the outside, it could be a sign of a leak in the cooling system itself.

The smell: Wet dog or mould

Smelling anything wet or mouldy is a sign of damp, so you need to find the source of the moisture. It could be caused by a build-up of condensation in your air-conditioning system, which isn’t draining out. This can also cause mould, so is worthwhile looking into this to return your car’s pleasant aroma.

The smell: Burnt rubber

If you can smell burnt rubber through your car radiator, it may well be an indicator of a loose hose or slipping drive belt, either rubbing or having landed on something hot. Let the car cool and open the bonnet to check that no hoses or belts are resting on the engine.  If nothing seems evident, you may need a mechanic to check all is well.


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