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Weird Smell Coming From Your Engine? Here’s What It Might Be

When an odd smell wafts up in or from your vehicle, it can be easy to ignore it. Whether it’s a reluctance to visit a garage, or you simply pass it off as probably being nothing, smells are some of the easiest signs of trouble that we can ignore. However, they can also be one of the most telling signals around that you need to book an engine repair. From problems with your fuel system to leaks in the exhaust, here are some of the most common smells to look out for and what they mean.

Smells Like: Burnt Rubber

As much as racing fans might love the smell of burning rubber on the tarmac, smelling this kind of scent any other time could spell trouble. If you’re smelling burnt rubber in the cabin of your vehicle, this could be an indication that belts or hoses have come loose or are wearing down. When hoses and belts are loose, they can come into contact with warm or hot parts of the engine, which ultimately leads to the burning rubber smell. In some cases, the smell could also be a sign of an oil or other fluid leak – whatever the case, this is definitely a smell you want checked out.

Smells Like: Rotten Eggs

If you’re getting a sulphuric smell, a lot like rotten eggs, coming from your vehicle, then there’s a high chance something isn’t quite right with your fuel system – usually, the catalytic converter. Sulfur gas leaks can make their way into the cabin of your car, and if the damage isn’t fixed early, can even pose a threat to your health and the safety of the vehicle overall. In some cases, it may be an easy fix but in others, you’ll need the help of a qualified mechanic.

Smells Like: Burning Carpet

If you’re smelling burning carpet or fabric, this doesn’t mean there’s a fire in the cabin – however, it could mean that your break pads are wearing down or too hot, or your rotors are overheating. The smell is usually caused by dragging or sticking brake calipers, or simply by brake pads that are too worn down or too thin. If you’ve had spongey brakes lately, it could be time to invest in replacements. 

If you’ve just had new brake pads installed, or you’ve been driving in stop-go traffic or steep downhill, this smell could be completely normal. Give your car a chance to cool down at the next available opportunity and call for help if you are unsure.

Smells Like: Burning Oil Or Smoke

If you’re smelling burning oil or a smoke-like smell this could be, believe it or not, an oil leak. This isn’t a smell or a potential problem you want to ignore, as a simple leak could lead to a much more serious problem or accident down the line. Leaking oil can get into all kinds of parts of the engine, including the timing belt or crankshafts, or if oil hits the exhaust, this could even cause a fire. If you smell burning oil, get your car checked out immediately.

Smells Like: Mould

No one likes the smell of mould and for drivers experiencing this in their car, it can be easy to pass off as just damp in the vehicle. However, this could be a sign that something isn’t quite right with your air conditioning. Air conditioning pulls excess moisture out of the air as it works, sending the moisture into a box behind the dashboard which will then drain out. If anything works it’s way into that box or over the drain, this can block it completely. The water then gets mouldy or stale, creating that unpleasant smell. If you smell mould, have your AC system checked out and prevent this issue in the future by running the AC every month or so for a few minutes at a time.

Smells Like: Burning Paper

If you’re smelling something similar to burnt paper, this could be a sign that the facing on your clutch is starting to burn and wear down. If the smell increases when changing gears, this is likely to be the issue. It can happen faster or more often if you are riding the clutch or stepping on the pedal too frequently and causing excess friction. The friction creates heat, which ultimately overheats and burns the facings, which are typically made of paper-based material. This could cause the entire clutch system to fail, so it’s important to have this checked as soon as possible.

Smells Like: Exhaust Fumes

If you’re smelling exhaust fumes in the cabin, this could be the sign of a leaky exhaust and is an issue that must be addressed immediately. If you smell this while on the road, roll down your windows and pull over as soon as it is safe, then get in touch with a qualified mechanic and have your car towed. Exhaust fumes can quickly raise the amount of carbon monoxide in the vehicle considerably, which can be fatal to the driver and passengers if not caught quickly.

Smells Like: Syrup Or Fruity Sweets

If you’ve been experiencing a sweeter smell in your car, typically one similar to maple syrup, this is likely to be coolant escaping the system. This could be from a leak, or simply because the cap hasn’t been secured correctly after the last refill. Without efficient coolant, your engine could overheat and cause lasting and potentially dangerous damage to your vehicle, so it’s important to stop the car as soon as possible, and have it towed to a trusted mechanic.

Smells Like: Burning Plastic

Burnt plastic isn’t a pleasant smell, and could be a sign of short-circuiting in the wiring of your vehicle. The plastic insulation on the wiring could melt or overheat if the wiring is shorting out, or a worn down insulation could cause overheating itself by allowing exposed wiring to rub together. This could then cause a fire which can be fatal. However, the smell could be as simple as a plastic bag caught up in the engine or on your exhaust. If you’re smelling burning plastic, make sure to pull over safely and check the engine. If a plastic bag is the culprit, don’t touch it until everything has cooled down. If you can’t locate the smell, make sure to take your vehicle in for repair.

Smells Like: Gas or Petrol

If you’re smelling petrol or gas in your vehicle, this is usually a sign of a leak which could be dangerous if not diagnosed and fixed. Raw fuel coming into contact with hot exhaust systems or other hot parts of the vehicle could cause a fire which can, of course, be devastating. Older cars, particularly those from before 1970, may emit this smell anyway, but it’s important to be safe and get your car checked out. Pull over immediately, and get your car towed to the mechanic.

For more advice on unusual smells or to book your car in for repair if you’re experiencing any of the above, get in touch with a member of our team, today.