Besides keeping you and your passengers comfortable, your car’s heater sometimes helps protect the engine from overheating.
But what does it mean when the car smells like burning rubber when the heater is on? The burning rubber smell in your car when the heater is on can mean many things, including a leaky heater core. It could also mean the cabin air filter is clogged or the drive belt is worn-out. Sometimes, the smell could be due to
- Blocked radiator, leaking valve cover gasket, or damaged resistor
So then, what is the solution to this problem? Read on to find out this and much more.
Causes Of Car Smelling Like Burning Rubber With Heater On Table
Here is a quick summary of why your car may smell like burning rubber when the heater is on and the solutions.
| Causes | How To Fix |
| Leaking heater core | Seal the leak with a sealant add-in |
| Replace the heater core and add coolant | |
| Blocked radiator or radiator fan | Clear the blockage using radiator flush and water |
| Bad blower motor resistor | Install new resistor |
| Clogged cabin air filter | Clean or replace the filter |
| Leaking valve cover gasket | Replace the gasket and spark plugs |
| Worn-out serpentine belt | Replace the belt immediately |
Why Does Car Smell Like Burning Rubber When the Heater Is On?- In Detail Discussion
Below, we will look at why your car may smell like burning rubber with the heater on and the solutions in detail.
1. Leaky Heater Core
The heater core is a small radiator designed to warm your car’s cabin using engine coolant. If the heater core is leaking some coolant, the coolant may burn and smell somewhere between burning plastic and rubber.
In most cases, you may smell the burning rubber only when the car is idle. And one of the symptoms of a leaky core heater is a damp carpet on the passenger side.
Additionally, some parts of the heater core made of plastic materials may melt, causing the burning rubber smell.
Solution
The best and most effective solution would be to replace the entire unit and top off the coolant if it is low. However, if the leak is minimal, you could fix the leaking with a sealant add-in. This is easier than doing the replacement.
2. Clogged Radiator or Radiator Fan
Your vehicle’s radiator and the fan may get clogged up with debris or dust over time. Due to the clogging, your car’s radiator may have difficulties circulating the coolant. If the radiator fan is clogged, it will not push the hot air out of the engine.
As a result, the coolant will boil over, causing your car to overheat and produce a burning rubber smell. This smell usually comes from the sizzling coolant.
Solution
- Drain the radiator and pour some radiator flush inside
- Then, start the engine and allow it to run for at least 15 minutes
- After the engine has cooled off, connect a water hose inside the radiator, fill the cap and run water through your car’s cooling system. This should clear the blockage.
3. Faulty Blower Motor Resistor
The blower motor resistor is made of a combination of plastic and metal materials. Typically, this resistor controls your vehicle’s fan speed.
This resistor may occasionally overheat due to mechanical obstruction, debris, and water. Unfortunately, when the resistor gets too hot, it may burn and smell like rubber.
Solution
The only solution here is to replace the blower resistor in the compartment housing the AC and heater.
4. Clogged Cabin Air Filter
Typically, you should replace your car’s air filter between every 15K and 30K miles. This is because the filter is prone to clogging up debris, dust, and dirt.
When this dirt build-up gets heated, it may cause a displeasing smell, including that of burning rubber. The burning rubber smell could also be due to the insulation on the wires burning or melting.
Solution
You can either clean or replace the cabin air filter if it is made of carbon or cloth. To clean the filter, gently blow air through it or use low-pressure water. But if it is made of paper, you will have to replace the cabin air filter.
5. Leaking Valve Cover Gasket
Over time, the valve cover gasket closer to the firewall may crack or break, or the bolts may become loose. This happens due to exposure to heat, dirt, and other elements.
As a result, the gasket may start leaking oil, and you may sometimes see smoke coming in from the vents. The leaking oil may eventually drip on the heat shields from the passenger side of your vehicle’s engine. And when you turn the heater on, the oil may cook up, producing a burning rubber smell.
Solution
You will have to replace the valve gasket cover with a new one. Also, you must change the spark plugs if the leaking oil from the gasket is pooling around the base of the plugs.
6. Worn-Out Drive Belt
Your vehicle’s drive belt, also known as the serpentine belt, is primarily made of rubber materials. Its main job is to transfer power to various components of your car, including the engine cooling fan and AC.
If the belt becomes loose on a pulley, it may slip, leading to heat build-up from too much friction. Because of the excessive heat, your car may start smelling like burning rubber.
Solution
Replace the worn-out belt, which is easy and relatively inexpensive. Watch this video and learn how to change the serpentine belt:
Tips To Prevent Burning Rubber Smell When Heater Is On
Now that you know what causes a burning rubber odor when the heater is on, how do you prevent it? Check out these tips.
- Always check your vehicle’s coolant level when the engine has cooled down. It should be between full and low marks.
- Inspect the engine regularly to ensure the gaskets, belts, and hoses are not worn out.
- Always look for any oil and coolant leaks around the engine compartment.
- Make sure to clean and change the air filter regularly, depending on your driving conditions.
- Check the radiator and radiator fan regularly for any dirt, debris, and dust build-up, and clean if any.
- Drive your car regularly. This will help keep the engine and all components adequately lubricated.
FAQs
Without further ado, let’s look at commonly asked questions regarding cars smelling like burning rubber with the heater on.
You can do this, but not for long, as the problem could result in more damage. Therefore, you must have your vehicle inspected by a professional mechanic as soon as possible.
This solely depends on the cause of the smell. For example, if it is due to a leaky heater core, the cost of parts and labor may range from $800 to $1000. Meanwhile, replacing a blower motor resistor will cost you between $115 and $150.
Yes, but only if you inhale the burning rubber fumes over a long period. For example, you could suffer from respiratory irritation. So, you must fix the problem immediately.
Bottom Line
Regardless of your car model or brand, you may occasionally experience a burning rubber odor when the heater is on. This may be due to the heater core leaking coolant or a clogged air filter and radiator fan.
Whichever the cause, the best solution is usually to replace the damaged component. That said, you should be pleased to know there are several ways to prevent this problem from occurring in the first place.