Car problems can be incredibly stressful—maybe because, if you’re not sure exactly what’s wrong, it could be nothing to worry about, or a big problem that’s expensive to fix.
However, diagnosing and addressing problems early is often the best way to prevent small issues from developing into serious, costly problems. A strange small is often one of the first things that people notice when something is wrong when their vehicle. If you notice a weird smell coming from the engine or in the interior of the vehicle, try to figure out what the issue is as quickly as possible. Below are some common strange smells that may come from your vehicle if something’s wrong, and what they usually mean.
1. Hot oil
Your vehicle should not smell strongly of oil. If you notice the smell of hot or burning oil, you likely have a leak somewhere. Generally, the leak is on the hot exhaust manifold if you can smell it starting to burn. If the crankshaft is leaking, then you should see some oil dripping to the pavement beneath your vehicle. However, the leak could also be coming from a valve cover, in which case you may see smoke coming from the exhaust. Always fix leaks quickly—you never want to drive with low oil levels. Plus, leaking oil can become a fire hazard.
2. Sulfur
The smell of sulfur resembles rotten eggs. If you notice this extremely unpleasant smell, you may have a problem with your catalytic converter. This auto part helps convert hydrogen sulfide in the engine to sulfur dioxide, which is less harmful for the environment. Sulfur dioxide should not have the characteristic rotten egg smell of sulfur. When this smell appears, it often means that the catalytic converter is not working properly and needs to be replaced. Get this part checked out as quickly as possible, especially if your vehicle is still under warranty. Unfortunately, the catalytic converter is typically an expensive repair due to the materials needed to make it.
3. Burning carpet
The smell of burning carpet is pretty distinctive. If you notice this smell as you drive, you may have an issue with your brakes. As soon as you notice this smell, stop and inspect your brakes to see if there are any glaring, visible issues. Often, this problem arises when a dragging brake causes excessive wear on the pads. This issue can usually be fixed fairly easily. You may also notice this smell if you forget to disengage the emergency brake. As you drive with the brake on, the pad will wear down quickly and cause the smell as the friction creates heat.
4. Mildew
A mildew smell is often associated with dirty bathrooms and locker rooms—places with lots of moisture. While you may be surprised to smell this in your vehicle, it could indicate a significant problem. Generally, the smell will enter your car’s interior after you turn on the air conditioning. It usually indicates that there’s mold growing on the evaporator in the air conditioner unit—unless, of course, there’s something else inside your car that’s causing the unpleasant odor, like an old gym bag.
Mold can trigger allergies and even cause serious health problems, so it’s important to fix this problem promptly. Try running the fan with the vents open and the air conditioner switched off to dry out the system. If this does not fix the problem, you will need to get the system cleaned.
5. Syrup
The sweet smell of syrup often catches people off guard when they smell it from their vehicle. Even though it’s not an awful smell like rotten eggs or hot oil, it usually means there’s a problem with your coolant. Ethylene glycol in coolant has a sweet smell that can be released when this fluid leaks. The leak may be from the radiator, a hose, or the heating system. This problem should be addressed quickly—you can damage the radiator if it runs dry, and the heating system can start to break down without coolant. Leaking coolant is also considered hazardous to the environment. Get a mechanic to assess and fix the leak as soon as you can.
6. Burning rubber
The smell of burning rubber is instantly recognizable. Typically, this smell signals a problem with the engine hoses and belts. Open your engine bay and see if there is anything obviously wrong. All the hoses and belts should be tight. Furthermore, none should be touching the hot engine block. If any part is touching it, wait for the engine to cool and see why the part has moved. If you can’t spot any visible problems, it could be possible that a belt is about to break. Have the vehicle checked out by a professional, and be sure to replace any parts with excessive wear to avoid a much more serious issue.