What Is An Exhaust Leak?


Leaks and cars go hand in hand, mainly thanks to their reliance on many kinds of automotive fluids. However, never forget that combustion engine vehicles can also suffer from exhaust leaks that involve harmful gasses coming straight out of the engine.

An exhaust leak happens anywhere on the exhaust system, between the manifold and the tailpipe. These leaks allow toxic exhaust gasses to escape into the surrounding environment, polluting the air. Worse yet, those gasses can enter the cabin and potentially poison its occupants. When you suspect that there’s an exhaust leak, shut the car off immediately to protect it from damage and you from health hazards.

Exhaust leaks are dangerous, but don’t worry. This guide will help you understand what signs to look for and what you can do to fix the leak if it happens to your car.

Related: Why There’s Gas Leaking from the Bottom of Your Car

What Is An Exhaust Leak In A Car?

An exhaust leak in a car happens when the engine’s gasses leak out of the exhaust system even before they can reach the tailpipe as they’re supposed to.

That might not sound like a big deal at first. Still, it’s extremely problematic and dangerous for the environment and the vehicle’s occupants.

You see, exhaust gasses are produced from the combustion process that happens inside the engine’s chambers. When the fuel and air mixture is combusted to generate power, it produces gasses like carbon monoxide, nitrogen oxide, and other harmful emissions.

Under normal conditions, those gasses flow through the exhaust system, where it’s filtered as much as possible before escaping the tailpipe into the surrounding environment.

However, an exhaust leak allows those gasses to escape while still very harmful to the environment. Worse yet, those gasses could end up inside the car’s cabin, causing health problems and even death.

Never forget that many harmful gasses, like carbon monoxide, are incredibly toxic to humans, especially in an enclosed space like the car’s cabin.

Aside from that, exhaust leaks also cause internal damage to the engine and trigger malfunctions in sensors attached to the exhaust system.

Given the danger of exhaust leaks, it’s critical that your car’s system be inspected regularly and fixed at the earliest sign of a problem.

Where Do Exhaust Leaks Happen?

Your car’s exhaust system has several components, and an exhaust leak can happen at any of them. After all, the system is exposed to the ground and debris underneath. In addition, hard objects like rocks can impact the exhaust, causing cracks and holes that leak harmful gasses.

Here are some of that system’s parts where exhaust leaks can happen:

  • Exhaust manifold, valve, or piston: These are the exhaust components in the vehicle’s engine. The exhaust valve and piston are inside the combustion chamber controlling the release of exhaust gasses. Meanwhile, the manifold is where gas escapes the engine and flows into the exhaust system.
  • Catalytic converter: This component is critical because it converts many toxic exhaust gasses to harmful emissions like carbon dioxide and water. Given its size, it’s often exposed to being hit by rocks that get kicked up from underneath the car while it’s mobile.
  • Exhaust pipe: Throughout the exhaust system, a pipe carries gas from the manifold to the catalytic converter and muffler. A hole in the pipe could quickly cause a severe exhaust leak.
  • Muffler: Lastly, all the exhaust gasses produced in the engine eventually pass through the muffler. This component reduces the noise coming out along with those gasses while controlling how fast they flow towards the tailpipe.

Understanding the exhaust system and its components will help you inspect and troubleshoot it for any potential leaks.

What Are The Signs Of An Exhaust Leak?

As a car owner and driver, you must understand what signs to look out for when there’s an exhaust leak. Aside from saving you plenty of money by repairing it while it’s small, you could also prevent dangers facing you and your passengers.

Some of the signs of an exhaust leak include the following:

  1. A strong gas smell: The clearest sign of an exhaust leak is a strong gas smell. The air inside your cabin should never smell of exhaust gasses under any circumstance. So, when that happens, you must assume an exhaust leak and pull over immediately.
  2. Warning lights: Another indicator is when warning lights start lighting up or flashing on your dashboard. The Check Engine light is the most common, though it doesn’t tell you the whole story of what’s happening. Still, seeing warning lights on your instrument panel and any other symptoms on this list suggest an exhaust leak is occurring.
  3. Poor fuel efficiency: Some minor exhaust leaks might go unnoticed, without any smell and without triggering any warning lights. Still, the engine’s performance will suffer when the exhaust system is compromised, and your car will have worse fuel efficiency than usual.
  4. Loss of power: The air and fuel that goes into an engine only make up half of the equation for your car engine. Besides that, the exhaust gasses must flow out efficiently for your engine to perform optimally. An exhaust leak undermines that and prevents the engine from producing enough power.
  5. Engine noises: Remember: gasses aren’t the only thing an engine releases into its exhaust system. Instead, it also lets plenty of noise out that way too. As such, a leaking exhaust system will cause you to hear loud engine noises from the engine bay and underneath your vehicle.

It’s already been said, but it’s worth repeating. When you suspect your car has an exhaust leak, the most important thing you can do is stop your vehicle and shut off its engine immediately.

How Do You Fix An Exhaust Leak?

The good news is that an exhaust leak is fixable. You can even do it yourself if you have the necessary skills and tools at home. Despite that, a repair that’s as crucial as this one should be left in the hands of professionals.

Regardless of who performs the repair, fixing an exhaust leak typically involves one or more of these methods:

  • Welding: One of the most permanent solutions to an exhaust leak is welding. That applies to any part of the exhaust system where the leak might form.
  • Patching: A low-budget solution would be to patch the leak with something sturdy like aluminum. You might save some money with this approach, but it’s not as strong as welding and still leaves your exhaust system at risk.
  • Taping or sealing: The cheapest solution is to tape up the leak using exhaust tape, sealants, or even some putty. However, these aren’t the solutions you can rely on and might only work for the short term (like maybe just to get the car to the workshop).
  • Parts replacement: Some leaking exhaust parts can be replaced entirely. For example, a cracked manifold is often replaced to give you better peace of mind.

Final Thoughts

An exhaust leak is hazardous to your car engine and the occupants inside. So, recognizing the signs and acting quickly is critical for everyone’s safety.

When you suspect that there’s an exhaust leak, you should stop the car immediately. You cannot drive the vehicle to the workshop as it’s too dangerous. Instead, get someone to fix it on the spot or have it towed to your preferred mechanic.

Remember: exhaust leaks are pretty straightforward to fix if you catch them early.

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