It is extremely cool to look at all the cars drifting and burning rubber in the movies. However, when you witness it in person, you will realise that these cool visuals are often accompanied by a horrible stench of burnt rubber. Sometimes, such a stench can even come from other parts of the car. So, what do you do when your car exhaust smells like burning rubber?

If your car exhaust smells like burning rubber, the list of potential causes might include burning of engine oil, coolant liquid, a slipping clutch or even a foreign object in the engine. Depending on which of these problems are occurring in your car, the fix can either be easy, or rather difficult.

It is important to note that the smell that seems to be coming from the exhaust, may not always originate there. It just might feel like it, but the real cause might be something else. Also, the smell of burning rubber can easily be mistaken. Thus, we have compiled a list of reasons that might lead to a foul smell while your engine is running.

Engine Oil

Burning engine oil is the most common cause of a car exhaust smelling like burning rubber. Now, as mentioned before, this may not smell exactly like rubber, but it can easily be mistaken for it. There are two possible ways that the engine oil is getting burnt.

The first one is that the engine oil is getting burnt on the exhaust pipes. This means that there is an exterior engine oil leak. This oil is then getting burnt when it lands on the exhaust pipe which generally has a temperature range of over 700-800⁰C. The second possibility is that the oil leaks into the combustion chamber and gets burnt along with the fuel.

You can tell the difference by checking the exhaust emissions colour. If you have a bluish-greenish hue to the exhaust gas, then your car is probably burning engine oil. If you see some smoke coming from the front of the car (not the engine), then there may be an external leak.

External leaks are generally caused by loose bolts, sensors, or even misaligned gaskets in some cases. Thus, it is easy to rectify but it is still a huge task to find out where the leak is originating from. There is also a possibility that it is not the engine oil leaking, but the transmission oil, which smells even worse.

Internal engine oil leaks are trickier. This can be caused either due to a problem in some gasket, or even a problem with the pistons. A professional can help you determine the exact cause. This may lead to an expensive fix, so be warned.

Coolant

When the engine coolant burns, it can sometimes be mistaken for burning rubber. Just like the engine oil, there are two possible sources of coolant leakage – internal and external. Therefore, the origin of the smell generated, and their causes are also the same.

External coolant leakage is more common and normally found due to a misaligned gasket or loose bolts. The location of a coolant leak is comparatively easier to find compared to engine oil leakages. This is generally found near the water pump or the thermostat of the engine.

The fix is equally easy, depending on where the leak has been found. You just need to realign the gasket and tighten the bolts. In the worst-case scenario, you might have to replace some parts.

An internal coolant leak is more dangerous and may lead to your engine failing completely. This generally happens due to a break in the cylinder head gasket and should be checked out immediately. Too much coolant leakage into the combustion chamber can cause the engine to break down.

An internal coolant leak can be identified by the white smoke coming out of the exhaust when the car is running. Before you run to your nearest garage, understand that you may also get this white smoke in the winters if you are living in very cold regions. Thus, no need to panic unless you are also experiencing a significant drop in power along with it.

The solution is to replace the cylinder head gasket or any other part responsible for the leakage. Unfortunately, this involves a significant amount of disassembling the engine and reassembling it. Thus, it is best to let a professional handle this.

Slipping belt

Various accessories in the engine like the alternator, water pump, or AC compressor are run by a belt attached to the crankshaft of the engine. Sometimes, what happens is that this belt starts slipping against the various pulleys that it passes over.

Because of this, there is greater relative motion between the belt and the pulley wheels and thus more friction as well. Since the engine is spinning at a very high speed, this slipping leads to high temperatures and thus burns off the belt.

Since the belt is usually made of rubber and other materials, this can very closely resemble the burning rubber smell. However, this would come from the front of the engine rather than the exhaust. A simple way to identify this is that you might hear a screeching sound every time you try to speed up your car. This sound is triggered by the slipping of this rubber surface on metal.

Fortunately, this slipping is very easy to fix. It is generally caused by a lack of tension in the belt. Thus, either the tension needs to be manually adjusted or the auto-tensioner needs to be fixed. It all depends on the car. If the wear to this timing belt is relatively high, you may need to replace this belt as well.

Slipping clutch

Previously, we saw a belt slipping. Another similar situation occurs when the clutch slips. Needless to say, this occurs only in manual transmission cars and it is one of the most common reasons why it seems like your car exhaust smells like burning rubber. This problem occurs when the frictional force between the clutch plate and its mating surface has reduced over time. As seen above, the slipping leads to heat generation and thus a burning smell.

To identify this is the problem with your car, you want to try accelerating rapidly. When you do this, you will see your rev counter rise very fast, but won’t feel the same amount of power in your wheels.

Fortunately, this problem is easily fixable. All you need to do is replace the clutch. However, since this too involves a lot of disassembly work, a professional will be able to help you in a better way.

To prevent this from happening in the future, it is important to improve the driving behaviour as it affects the clutch’s life significantly. Remember to engage and disengage the clutch gently rather than driving like you are in a fast and furious movie.

Foreign object in the engine

Finally, a last possible cause of the burning rubber smell in your car exhaust is because of some foreign object that has entered inside the engine. This can be anything from small leaves to silicone gaskets. Carbon-based contaminants will result in a blackish colour exhaust emission.

Depending on the size of the contaminant, you can even let it be as the object might burn itself out in a matter of days. If the smell still persists, then maybe it is time to take your car to the nearest dealer and have them explore other options.

It is worth noting that you can also see black smoke when your engine is not burning the fuel efficiently. Thus, if you see something like that, you might want to confirm the cause of the smoke from a professional.

Final thoughts

Hopefully, this article helped you understand the most common causes of why your car exhaust smells like burning rubber. People generally take this smell very casually. But as you have seen, this can indicate something very minor like a worn timing belt to something major like the cylinder head gasket having a leak in it. Thus, it is important to quickly become aware of the situation and diagnose the exact problem.

Based on this, you can then decide whether it is worth it to get it checked immediately or whether you can afford to wait a little longer. You might be able to find a few DIY solutions in the owner’s manual. If not, you can always ask your nearest dealer to take a look at it. We hope you stop smelling that foul odour soon!