My Car Smells Like Burning Rubber When The AC is on

The most common cause for your car smelling like burning rubber when your AC is active is because of low coolant levels. The lack of coolant makes some internal AC components endure more heat than they should, which can lead to melting and burning, releasing the smell.

Still, many other problems can cause a burning rubber smell when you turn the air conditioner on. Commonly, problems in this context will probably relate to electrical issues.

Watch out: The burning rubber smell popping up when the AC is on indicates that something is enduring too much heat. Whether that'll be damage to internal AC components, electrical, or engine-related, your car is running risks like fire hazards, mid-traffic shutdown, toxic fumes release, etc.

Many problems might be happening while the smell spreads, leading to an unsafe hot engine, untrusty brakes, burning oil, and lack of power steering.

Therefore, the best approach is to investigate the burning rubber smell when you detect it. An investigation in a certified auto shop will help you understand the problem's severity and which actions to take.

The most common causes of a burning rubber smell when the AC is active

Many problems can trigger a burning rubber smell from a vehicle after the AC is active. These are the most common ones:

• Low refrigerant fluid: Lack of coolant can make AC components unprepared to endure the system's heat. Therefore, these components can burn or melt.
• Slipping serpentine belt: A slipping serpentine belt, for example, might slip out of place and rub against hot components near it. This can cause a burning rubber smell since the belt is rubber.
• Electrical Issues: Faulty wiring or an overheating electrical component in the AC system can also cause a burning smell.
• AC compressor issues: If the compressor is working too hard or is malfunctioning, it can overheat and produce a burning smell.
• AC clutch or pulley issues: Problems with the AC compressor clutch or pulley can cause friction and lead to a burning smell.

Frequently Asked Questions

Can a dirty air filter cause a burning rubber smell?

A dirty air filter itself shouldn't make you smell burning rubber. It's more likely a sign of something else overheating from restricted airflow.  The culprit could be a slipping belt, overheating clutch, transmission fluid, catalytic converter, exhaust pipe, exhaust system, or even a stressed AC compressor - all of which can burn rubber under friction.

Does carbon monoxide smell like burning rubber?

No, carbon monoxide is odorless and tasteless, so it doesn't emit any weird smell. That's why it's called the "silent killer." Burning rubber might be a sign of something else overheating, but if you suspect a carbon monoxide leak, don't rely on smell -  get everyone out of the car's cabin immediately and call emergency services.  Also, install carbon monoxide detectors in your home for early warning.

How do you find the source of an electrical burning smell?

If you detect a burnt rubber electrical smell, prioritize safety first. Turn off the power at the breaker box and evacuate if the smell is strong. Once it's safe, look for hot outlets, switches, or appliances. Unplug anything suspect and visually check for scorching or frayed wires. If the source remains elusive, call a qualified electrician - electrical issues can be dangerous and pose a fire risk.

Typical fixes to address the cause(s)

• Radiator Replacement

• Air conditioning compressor replacement
• Air conditioning hoses replacement
• Cooling system flush
• Serpentine belt replacement
• Cooling fan replacement
• Coolant replacement

The most common cause: Low refrigerant fluid

The most common reason for a car smelling like burning rubber when the AC is on is because of low coolant. The lack of coolant in the AC system means that the heat from internal components working won't have a refrigerant substance to avoid overheating.

The coolant is a refrigerant substance that absorbs heat, cooling down the system and ensuring the inner temperature is safe. If there's no refrigerant to cool down the system, the temperature will rise and become unsafe.

Many components inside the AC system can burn and melt, creating a burning rubber smell. If these components are under high heat, they'll suffer from overheating and consequently melt.

Therefore, the lack of coolant causes overheating, which results in components inside the AC system burning and melting.

What exactly is the coolant?

There are different coolants for the engine and air conditioning system in a car.

• Engine coolant also known as antifreeze, is a liquid mixture that circulates through your car's engine. It acts like a heat transfer agent, absorbing heat from the engine and carrying it away to the radiator where it gets released into the air.

• Air conditioning system coolant is actually called refrigerant, not coolant. It's a different kind of liquid that absorbs heat from the car's interior air and releases it outside through the radiator. Common refrigerants are R-134a and R-1234yf, neither of which are water-based.

Go safe: Ask a mechanic to inspect your vehicle and investigate the causes and solutions for your vehicle's burning rubber smell. It's better to discover the issue's severity quickly, so you can prepare yourself and avoid further problems. Mechanics perform a vehicle inspection, which aims at fixing the problem entirely and discovering all underlying problems.

What’s a vehicle inspection? It’s “detective work” on your vehicle, checking its systems to find if anything is preventing the car from working as expected. In this case, mechanics examine different parts of your vehicle to track where the burning smell is coming from and what’s causing it. They’ll also check the condition of components during their inspection, noting which are causing the problem and which got affected by it, recommending to replace them in order of priority.

Transparency example in an AC compressor replacement

Let's see how exactly a certified auto shop that focuses on transparency investigates a burning rubber smell that only appears when turning the vehicle's AC on.

First, the auto shop would get the customer's complaint, noting every relevant detail about the vehicle's problem. In this case, the customer complained about the burning rubber smell from the AC.

The vehicle inspection starts with a focus on the AC system. The mechanic starts the car and does tests by turning the AC on and driving for a few miles to see if they can replicate the issue.

After replicating the issue, they start checking inside the AC system. In this case, they instantly knew the system was overheating since some inner components were partially melted.

After checking the AC compressor, they found leak signs around it, meaning refrigerant fluid was leaking and the compressor was overheating, damaging surrounding components.

In this case, the mechanic put the "immediate action" tag on the compressor and surrounding melted components since they ere the vehicle's priority fix at the moment.