Catalytic converters are designed to reduce car emissions, but if your catalytic converter smells like burning rubber, it could signify something more serious. It smells like burning rubber if you sniff them. However, what are the underlying causes?
So, why does the Catalytic converter smells like burning rubber?
An odor of burning rubber could indicate that a rubber hose or belt under the hood has become loose. A damaged or worn-out drive can also cause this problem. The smell of burning rubber may even result from a gas leak in a fuel tank.
Interested in finding out the possible causes and what steps can be taken to prevent them from happening? Follow along!

Why Does Your Catalytic Converter Smells Like Burning Rubber? (8 Reasons)
Burning rubber is caused by several factors. Below are some of them explained in detail with proper explanations of why and how they occur. Let’s learn more about it.
#1 A Loose Rubber Hose
A loose rubber hose can cause burning rubber smell rubber.
A hot engine component can melt a fuel or vacuum hose. There might be a burning rubber or plastic smell.
To prevent melting and excessive vibration, factory clips should be used to secure engine hoses. It is not uncommon for older vehicles to have lost or broken these clips.
So, how do you identify a loose rubber hose? You can check out the acoustic valve; look down the gap underneath your airbox “air feed,” it will plug into that is still there. The pipe should be blocked off if it is not.
#2 Fuel Leak
The burning rubber smell can also be caused by an oil leak that’s been dripping down onto your catalytic converter and causing it to overheat from lack of lubrication.
A leaky gasket or cracked manifold may be causing this type of problem on your car, so make sure you have your vehicle checked out by an automotive technician as soon as possible if you notice this odor coming from under your hood!
#3 Sticking Brakes
It’s common for brakes to stick. When your brakes stick, you’re going to get a ton of heat, and if you’re lucky, you’ll get a fire.
People often don’t realize that brake pads contain rubber, which can cause sticking brakes to create a lot of heat.
Brake calipers and brake pads that stick are the most common causes of sticking brakes.
After a short drive, feel your wheels to determine if any are hotter than others. You should be careful when handling these brakes since they can get incredibly hot.
#4 Defective Oxygen Sensor
The most common cause of a catalytic converter smell is a defective or failing oxygen sensor or O2 sensor. The oxygen sensor monitors the amount of oxygen in the exhaust system and controls how much fuel is added to the engine based on that reading.
If there is not enough oxygen present, then the engine will run rich and produce an overly rich fuel mixture. The resulting excess fuel can overheat and ultimately damage components such as the catalytic converter and wiring harnesses.
This smell is caused by the oxidation of sulfur in gasoline, which can be quite pungent and easily detected in exhaust fumes. The sulfur reacts with oxygen in the air to form sulfurous acid (H2SO3), which has a strong smell similar to rotten eggs.
#5 Carbon Buildup
Another possible cause of catalytic converter smells is carbon buildup on valves or rings within the engine itself. This buildup can cause misfires and increase temperatures within the combustion chamber.
The increased temperatures then begin to degrade components such as seals, gaskets and hoses, potentially causing leaks within these systems as well as excessive smoke from under hood from these leaks.
#6 Overheated Brakes or Tires
When you feel like rubbery smell, this might be also an indication of overheated brakes or tires!
Overheating is usually caused by a slipping clutch or a malfunctioning clutch. You should let the car cool down if you experience this smell while using your clutch. However, the smell should be carefully monitored even if it does not require immediate auto care. Consult your mechanic if it persists.
Brake pads can also cause a burning smell in cars. Putting too much pressure on your brakes can cause them to overheat. If the smell persists, try downshifting. It is also a good idea to check your tires’ exteriors. The brake pads are likely to be the cause of unusually hot brakes. Contact your brake pad manufacturer to schedule an appointment.
#7 Radiator Coolant Leak
Cooler is the central cooling system of your car! The system also acts as a barrier to prevent leaks. In case it fails you can also feel such rubbery smell!
The smell of a leaking coolant might not be the exact same as burning rubber however its pretty close to it. The smell is kind of sweeter than the rubbery smell. The moment you smell such a smell, you should immediately seek out the leaks.
#8 Short Circuit
An electrical short smells somewhat like burning rubber if you have ever experienced it.
Try to smell any extra rubber smell in the fuse boxes inside and outside of your car.
Fortunately, most electrical wires are fuses, so a short usually lasts a moment or two.
Final Words
Nobody likes burning smell of catalytic converter. Why should they? The pungent smell shouldn’t be nice. Worse yet, the smell is a cautious signal of your vehicle’s serious problems.
So, there’s no room left for ignoring the smell. Rather you should immediately start figuring out the root causes of it. That way, you can use the bad smell to your advantage and find out the problem before it’s too late.
And, for your convenience, I’ve laid out all the possible causes behind catalytic converter’s smells of burning rubber. As you have read the article you can now act on it more intelligently than others.
Best wishes to you. Wait! If in your case the smell turns out anything worse other than the mentioned above causes, please let me know in the comment.