There are few things worse than getting in your car and getting a whiff of an unfamiliar and potentially awful smell. It is likely that you have no idea where it is coming from, whether it is an old sandwich that slipped under the seat or something wrong with your car. Determining what the smell is and how to fix it are two entirely different problems, especially if it is an issue under the hood or with the exhaust. Perhaps the first thing would be to do a deep clean of the interior of your car, pulling out the seats and taking out the floor mats to get rid of all the crumbs, dust, dirt, pollen, old food, and anything else that might be hanging out in the nooks and crannies. In some cases, it may be better to take a break from driving until you figure out what is going on and how to resolve the problem. This is where Wrench comes in! One of four highly-skilled, ASE-certified mobile mechanics can come out to your preferred location and determine what is wrong, or fix the issue on the spot. You do not have to worry about driving your car to the shop, or worse, hiring a tow truck if you are not able to drive your car.

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How to detect unusual smells in your car is not something they teach you in driver’s education or something you pick up even after spending years on the road. There are so many possibilities as to what it could be and most of us probably have no idea how to figure out where it is coming from. The worst thing you can do when you smell something unusual in your car is ignore it. In the best case scenario, you accidentally left an apple core in the backseat of your car. However, the worst case scenario may be a carbon monoxide smell which is can be extremely toxic for humans to ingest.

How to avoid unwanted smells

One of the best pieces of advice we can give is to stay up-to-date with the maintenance schedule in your car’s owner’s manual. Wrench is here to help keep you safe and your car healthy but we can only do that if you schedule regular appointments! Although it may seem counterproductive, routine maintenance can actually save you a lot of money in the long run because you will be able to catch any issues you may have early, and hopefully avoid larger problems like a failing engine or rusty brake pads. Additionally, keeping up with maintenance will help prevent unwanted smells because you will be taking care of all of the parts of your car that could cause odor-related issues. As soon as you start smelling something weird, do a quick check around your car to see if you can figure out where it is coming from before you determine the best course of action.

Common car smells that may be a sign you need a service

  • Must. If your car smells musty when you turn on the air conditioning, this could be a sign that there is mildew or mold build-up in the interior. It is common for moisture to collect in the air-conditioning system but this does not mean it should be ignored. A simple way to remedy this is to run the fan on high for a little while to dry out the system, but monitor it to make sure that it does not get worse. A continued musty smell could the sign that there is a clog in the drain tube, which may need professional help to fix.
  • Rotten eggs. If your car smells like rotten eggs, that is likely a sulfur issue (unless you have a days-old egg salad sandwich hiding under your seat). Your car’s catalytic converter is meant to convert engine exhaust into sulfur dioxide, but if the part is faulty, it could lead to your car smelling an awful lot like rotten eggs, which is never fun. This a very popular service at Wrench and one of our many talented mobile mechanics would be happy to replace it for you.
  • Burning rubber. The smell of burning rubber could have something to do with the engine belts coming loose. If your engine is on the older side, it is very possible that the belts or hoses need to be replaced in order to remedy the smell. For more information on how long an engine normally lasts, click here.
  • Burnt carpet. If the burning smell is less like rubber and more like carpet or fabric, this indicates a brake issue as opposed to the belts and hoses. It is still a good idea to get it checked out because you never want to find yourself with faulty brakes.
  • Sweet. A sweet smell is probably not just an old cinnamon roll that got left behind, but likely a leak in the antifreeze. Antifreeze has a uniquely sweet smell that would be good to take note of so you can pick up on it if there happens to be a leak. Breathing in antifreeze for too long is not good for us, and the source of the leak can be difficult to locate if you do not know what you are looking for, so it is best to consult with a professional in order to get the matter taken care of as quickly as possible.

Smells you absolutely should not ignore

  • Exhaust. If you smell exhaust fumes inside your car, this could be a sign of carbon monoxide leaking from the exhaust pipe, muffler, or somewhere else in the car. This is a sign that you should book an appointment with Wrench immediately and stay out of your car until you get the issue resolved. This is one of the best reasons to carefully monitor any smells you notice because they could be potentially dangerous.
  • Gas. If the car smells like gasoline and you do not remember spilling any the last time you were at the gas station, this could be the sign of a much larger issue and you should stop driving your car immediately because it could potentially be flammable. Schedule a diagnostic appointment with Wrench so that we can come out to your location and figure out what is going on. The mechanic will be able to determine where the smell is coming from and what must be done to get you back on the road.
  • Burnt toast. In this case, definitely not your leftover breakfast. This is the sign of an electrical issue and should not be taken lightly. Whether it is a short circuit or a blown fuse, both could lead to an engine fire if not handled properly, so this is not an issue to avoid.  

As you can see, there are lots of smells that all correspond to different issues. The best thing you can do for your car is educated yourself on what to look for (in this case, smell for) to keep your car in the best condition possible and running for years to come. Remember, if you are ever unsure what the issue is, schedule a diagnostic appointment with Wrench, and a mechanic will be out to your location in no time to figure out what is wrong. At Wrench, your safety is our top priority, which is why we want to do everything we can to keep your car running for as long as possible. If you have any more questions about our services or using Wrench in a global pandemic, feel free to contact our customer service team by email, at, or by phone, at 844-997-3624.


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