Bad odours from the car are a tell-tale sign that something is wrong with your vehicle. An unusual smell from car engine, like something burning, can indicate a potential risk ahead or the malfunctioning of the car’s engine. 

Just as with visual checks, you should be able to detect different car engine smells and the issues associated with them. This will make it easier to troubleshoot faults with your car and take immediate action. Also, detecting these warning signs early could prevent significant breakdowns and failures, saving you pricey repairs later.  

Here are the most common car engine smells you should be wary of, what mechanical loopholes trigger them, and how you can resolve them.  

   1. Mould or Musty Smell From Car Engine 

If you sense a mould or musty smell in your car, especially during warm weather in Spring, the air conditioning unit may be the potential cause. 

Your car’s AC unit comprises a box with a drain that stores the extracted water from the moistened air outside. Over time, dust, leaves and other debris make their way to the drain and clog it. 

The standing water eventually turns mouldy, leading to a foul odour from the car. The issue can further escalate if the mould-spawning moisture builds up in your duct system when not in use.

Solution: In case of mould smell from the car, get it checked at a reliable car service centre. They will also check if oil seals and bearings need lubrication to make them last longer. Also, run your AC twice a month for a few minutes (even if you don’t need to cool off) to prevent moisture buildup. 

    2. Smell Of Burning Oil or Acrid Smoke 

Ever asked, “why is there a burning smell coming from my car?” If your car smells hot or smoky, it can be possible for two reasons: there’s a problem with the oil, or the car’s engine is overheating.

In both cases, you need to take immediate action as it may result in fire or damage to the engine. 

If you notice the smell within a few hours of an oil change, a loose filter, drain plug, or an oil cap could be the cause.

Solution: Take your vehicle to the mechanic and get the oil leakage checked or ask them to tighten the filter, drain plug or oil cap properly. 

   3. Smell Of Burning Rubber

Such an odour indicates a slipping engine belt. Another reason could be a hose from the power steering or cooling system that is rubbing on a belt and has begun melting. 

Solution: Let your car cool down. You can then open the hood and check for your hoses and belts. If you can still sense the smell, take the car to the professionals. 

    4. Smell Of Rotten Eggs

A smell similar to rotten eggs or sulphur could mean an issue with your catalytic converter. It is a sign that your catalytic converter may not be processing hydrogen sulphide properly in the exhaust. Note that Sulfur is a byproduct neutralised by the catalytic converter and filtered out from the exhaust. 

A faulty catalytic converter could indicate that your car isn’t street-legal. Also, the longer you wait, the higher your repair cost.

Solution: Immediately take your vehicle to the mechanic and have your catalytic converter checked. Ask them whether you should switch fuel brands.

    5. Smell Of Burning Plastic

If you notice an acrid, burning plastic smell, it could be a sign of a short circuit in the wiring. First, check for the undercarriage. It is likely that litter from the road (potentially plastic) has caught under your car and melted due to engine heat. 

If you found no issues with an undercarriage, open the bonnet and inspect your car’s wiring near the battery. Electrical or battery issues can cause plastic casings to melt. If you want to know more about battery issue please visi our blog: www.bcsworkshop.com.au/car-repairs-melbourne/batteries-and-testing/

Solution: Pull over immediately and safely. If the problem is the burning of the plastic litter, try to remove it as much as you can. Be safe, or you could risk a fire. If you sense a problem with the car’s wiring or battery, take your vehicle to a professional for diagnosis and get it repaired. 

    6. Smell Of Burning Carpet

If you notice the smell of a burnt carpet when keeping your foot on the brake going down a steep, it can be a sign of overheating of brake pads or rotors. If this persists for a long, it can lead to premature brake wear or even brake failure. Another reason for this type of smell from car engine could be the sticking or dragging brake callipers or thin brake pads.

Note: If you’ve replaced your brake pads recently, you may sense a similar odour for the first couple hundred miles. 

Solution: Pump the brake on and off if you are going down the steep. If the smell persists, visit the mechanic to have your brakes inspected.

    7. Smell Of Maple Syrup or Fruit Candy

You could notice this unusual odour when you’ve just switched on the ignition or when your car is parked. A sweet, syrupy smell indicates a cooling system leak, with coolant/antifreeze escaping from the seal.

Coolant/antifreeze contains a chemical compound, ethylene glycol, that smells sweet. In case of a leak in the cooling system, the fluid can drain through the undercarriage of your car and drip onto the road. This may cause a sweet syrupy smell that is sometimes difficult to miss.

Solution: If you find a leak in the cooling system, get it repaired to prevent overheating. The fluid is toxic, and its sweet smell attracts animals. So clean up any leaks if pooled under your car to safeguard pets or animals. 

    8. Smell of Fumes or Exhaust 

If you smell fumes or exhaust while driving, especially when you’re driving slowly, it could likely be due to a leak in the exhaust. This is an indication of dangerous levels of carbon monoxide entering the cabin.

Exhaust leaks are often caused by corrosion, causing small holes or cracks. This results in fumes lingering under the car, rising through the floor and into the cabin.

Solution: Take your vehicle to the mechanic, get it inspected for a leak and ask them to repair it if needed. 

Wrapping Up 

Your car needs proper care and maintenance. You want to know what's causing that foul smell so you won't have to worry about potential losses. So, the next time you notice a peculiar smell from car engine, reach for Ford service Clayton at BCS Workshop. 

Our specialists and innovative repair system will detect the potential cause of unusual smells and provide a permanent solution to your problem. And If your vehicle, whether a Kia, BMW, Audi, Volkswagen or any other car, requires a routine check-up or maintenance service, we've got you covered, book our services now.