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How Long Can I Drive With An Exhaust Leak? When to Stop Driving

A broken exhaust bracket leading to an exhaust leak.

An exhaust system is designed to keep your car quiet. It is also responsible for safely transporting the toxic fumes from the engine out the rear of the vehicle.

Yet sometimes, it can develop leaks. Is it safe to drive the vehicle this way? How long can you drive with an exhaust leak?

How long you drive with an exhaust leak depends upon where the leak has developed. For example, if your engine manifold is leaking, driving can introduce exhaust fumes into the car's cabin, so you should not drive it at all. But if you have a leaky muffler, you can drive as long as you like, but it will be a noisy ride, and you risk being pulled over by the police.

An exhaust system typically consists of three parts — the exhaust manifold, the downpipe, and the main silencer or muffler, all of which can develop leaks.

Let's look at an exhaust system leak's seriousness and what happens if you don't have it repaired.

Table Of Contents [show]

    A broken exhaust bracket leading to an exhaust leak.
    A broken exhaust bracket leading to an exhaust leak.

    How Serious Is An Exhaust Leak?

    An exhaust leak can let poisonous gases, like carbon monoxide, into the passenger cabin, reduce fuel efficiency, foul oxygen sensors, and cause catalytic converter failure and internal engine damage. Besides, it also makes your car noisy.

    An exhaust leak makes your car loud regardless of which part of the exhaust system it has developed.

    Besides being embarrassing, the situation can be hazardous.

    The exhaust plumbing carries fumes and combustion byproducts away from the engine.

    If a leak develops, it can allow harmful substances into the vehicle's cab.

    Introduce Toxic Fumes Into The Cabin

    The passenger cabin of a car is not hermetically sealed. Instead, it relies on the exhaust system to safely expel the exhaust gases from the car's rear.

    If the exhaust manifold leaks, these harmful gases find their way into the vehicle's cabin instead of making their way outside.

    The silent killer carbon monoxide is also a combustion byproduct. You won't even know it leaks into your cabin until the worst happens.

    Decrease Fuel Efficiency

    Exhaust leaks can throw off the air-fuel ratio balance. This dupes the oxygen sensors to think that the combustion mixture is lean, drawing more fuel into the combustion chamber to compensate.

    This significantly lowers your car's fuel efficiency, leading you to refuel more often than usual.

    Cause Catalytic Converter Failure

    You have already read about the extra fuel being drawn into the combustion chamber. But since the actual amount of air present is not enough to burn all the fuel, the unburnt fuel is pushed towards the exhaust stream.

    This fuel is not as insignificant as you think.

    It travels to the catalytic converter, which operates at extremely high temperatures. Upon entering this part, the fuel combusts, damaging its interior substrate and clogging it, so it does not function correctly.

    Destroy The Oxygen Sensors

    The unburnt fuel is also responsible for destroying the oxygen sensors of your engine. It can coat the tips of these sensors, preventing them from taking a correct reading.

    Besides lowering your fuel efficiency, a poorly performing oxygen sensor can sap power from your engine and make your car idle poorly.

    If you ignore the issue for too long, you might need to replace your oxygen sensors, which may be indicated to you by a check engine light.

    Sabotage Internal Engine

    This is the most serious impact of an exhaust leak. If your car develops one in the wrong place, say by the exhaust manifold, it can lead to a painfully expensive engine repair.

    A leak close to the exhaust manifold prevents it from taking away the extreme heat from combustion.

    When it stays there, this heat can damage the engine valves that let the exhaust fumes out of the engine.

    Repairing such damage costs thousands of dollars, which you won't be keen on spending. That's why you should not ignore a much cheaper exhaust leak and get it fixed as soon as possible.

    A mechanic looking for an exhaust leak.
    A mechanic looking for an exhaust leak.

    What Are Signs Of An Exhaust Leak?

    Unusual engine sounds, vibrating gas pedal, loud noises while accelerating, bad fuel efficiency, and strange smells are common signs of an exhaust leak.

    Let's go over each sign of an exhaust leak in more detail.

    Unusual Engine Sounds

    When you ignite the engine, and it emits a noise that keeps getting louder, it is an unmistakable sign of a leak in the exhaust manifold gasket.

    The gasket sits between the engine block and the piping from the exhaust manifold. Along with piping, the gasket gets heated and cooled, which can cause corrosion and leaks.

    Vibrating Gas Pedal

    Vibration is another sign of a leaky exhaust. You can tell your exhaust has developed a leak when your gas pedal vibrates every time you step on it.

    If the leak is small, the vibrations will be low, but as it increases in size, so will the vibrations, extending to the steering column and floorboards to the point where the whole cabin appears to be vibrating.

    Loud Noises While Accelerating

    A roaring sound is completely natural whenever you accelerate. But your exhaust might be leaking if you hear sounds that seem like whistling or air leaking. However, you should not rely on this symptom alone. Use it only when you have already witnessed another symptom.

    Strange Smells

    Carbon monoxide may be odorless, but it is not the only fume that the exhaust system expels.

    If your exhaust system leaks, you might notice a strange burning smell inside the cabin.

    This can happen when the exhaust manifold becomes damaged. Since it is responsible for gathering and sending the combustion byproducts away, if it starts leaking, the exhaust fumes and gases will find their way back to the engine or cabin, making it smell.


    Driving with a leaky exhaust can harm your and your car's health. Even if you notice just one symptom of an exhaust leak, you should take it as a warning, get your vehicle to a mechanic, and have your exhaust system fixed inexpensively; otherwise, you could damage the engine, which is very expensive to repair or replace.