Symptoms of an Exhaust Leak in Your Car Engine

Exhaust pipe on the back of a car

A car exhaust system is one of the most important parts of any vehicle. Making sure your exhaust is not cracked and leaking is integral to your own safety as well as the performance of the car. Luckily, it does not take long to troubleshoot the symptoms of an exhaust leak, find the specific problem, and fix it.

What an Exhaust System Is

The exhaust pipe is part of the overall exhaust system and can be seen underneath the back of your car. If your exhaust pipe has a hole or a leak, your engine performance will be affected.

We'll go over some easy-to-spot signs of an exhaust leak and how to find where an exhaust leak is located. If you have an older car, it can be harder to notice some of these common exhaust leak symptoms as they tend to be a little noisier and less efficient.

However, some exhaust issues cannot be missed, nor should they be. Having a properly functioning exhaust system is key to the overall health of your car so it is important that yours works correctly and does not have any issues.

If an issue does arise, fix it immediately. Don't wait around and hope it gets better. If you do this, the issue may become worse and more costly to repair later on. It may also mess with your ability to safely drive your vehicle.

Common Noises that Indicate an Exhaust Symptom Leak

Your car will make some interesting noises if your exhaust has a hole in it. Luckily, these noises are usually pretty easy to detect making it easy to know if you have an issue with your exhaust system that requires your attention.

The hole in your exhaust system that is causing the noises you are hearing could be caused by metal corrosion which often takes on a brown hue which is easy to spot on the system if you take a look at it.

Metal corrosion can cause the pipe to break down from oxidation. This type of noise will be unmistakably loud and will be the most noticeable while you are accelerating the vehicle.

Another noise you could hear is backfiring while your car is in motion or idling which can actually be quite alarming to hear if you are not expecting it. Make sure you don't slam on the breaks just because you hear this sound if you are in traffic or somewhere else where doing so could be dangerous. Instead, pull over when it is safe to do so.

If air is mixing with the fuel it will create back pressure which can cause backfiring. This reduces the performance of the engine and possibly even fuel economy for fuel injection engines.

Any noise will be louder and higher pitched than your car's normal running sounds which is why it is the most noticeable symptom of an exhaust leak. The sound will be different from chugging, which is a common sound associated with a blocked exhaust pipe.

Exhaust System Visual Inspection

It may seem like a given but if you are worried about your exhaust system, take a look at it. Use a car jack to raise the car and ensure the weight of the vehicle is supported with jack stands, giving you enough space to slide beneath the car. From here, you should be able to give the exhaust a thorough visual inspection.

Make sure you are very careful and use the utmost care when putting the vehicle on jack stands so you do not injure yourself. If you have never done this before, ask for help from someone who has. Don't risk hurting yourself or someone else.

Once the car has been safely raised by the jack stands, look for any obvious signs of rust damage or any areas where part of the exhaust may be broken or cracked. Do this for every section of the exhaust pipe and use your hand to check that each component of the exhaust system is not loose.

You should take a flashlight with you before you get underneath the car so that you have a better view of the system, including the color so that you can spot any corrosion or spots easily. It would be awful if you missed something major due to improper lighting.

Tailpipe Smoke

Exhaust comes out of an exhaust pipe.

Smoke coming out of a tailpipe is another sign of an issue with an exhaust system. To can test to see if your vehicle has this issue, Start by turning the car on and giving the gas pedal one or two heavy pushes.

If you have a leaking exhaust system, smoke will flow out of the leaky part or crack at this point. Have a friend or a family member with you to help identify where the problem is and whether you can fix it yourself or need to take the car to a garage.

If there is a lot of smoke, you may want to wear safety goggles when looking for the issue or a safety mask if you want a closer look at where the smoke is coming from. Otherwise, you will end up breathing in exhaust fumes and having a hard time seeing what is happening.

Don't touch the exhaust pipe. It will be hot to the touch and could even burn your hand.

Do this outside and not in an enclosed area like a garage. If there are fumes you will want to be in an open area for health and safety reasons.

Smoke Color

Smoke is also a sign of an issue with your exhaust system. The color of the smoke emitting from your tailpipe as the car runs can actually help you determine what type of liquid may be leaking and save you a lot of guesswork. This can also help you understand if the issue is one you can solve yourself or one you will need to let the professionals handle.

Start your car’s engine and check the color of smoke coming out of the car’s tailpipe. If the smoke is black, fuel is not being properly burned during the car's catalytic combustion process. Unburned fuel is being sent through the exhaust pipe. It is incredibly important that you fix this issue as soon as possible.

If the smoke is a blue/gray color, however, it means engine oil is leaking into the combustion chamber. If the leak is severe, it might even come out of the exhaust pipe directly as you run the car, which would mean any dark liquid you see is actually oil and not a soot-water mix. Again, this is an issue that should be fixed quickly. Not doing so can cause bigger issues later on.

If a lighter, white smoke is coming out from the exhaust pipe, you have to check the engine to determine the cause. Start by popping the engine and grabbing a flashlight to make it easier to see what is happening inside of your engine.

You can now check the combustion chamber of the engine. If there is a lot of leaked oil inside, it could indicate the car's piston oil rings are worn and are allowing oil to enter the combustion chamber. This is also an issue that you should take care to fix to not cause bigger issues later on.

Soot Deposit in the Exhaust Pipe

If there's a soot deposit on the exhaust pipe, the dripping blackish oil-like liquid that you think is engine oil could actually be a mixture of condensation from the car exhaust and the deposited soot that is leaking.

To see if this is happening in your car, put on gloves and run your finger on the inside of the exhaust pipe to check for soot that may have settled there over the years. If there's a lot, you will need to clean it out and remove it from the engine. You will also need to fix the root of the issue so it does not become a problem again.

Before you touch the exhaust pipe, make sure your vehicle is off and has had a chance to safely cool down so you do not burn or irritate your hand by touching a hot pipe. By waiting just a few minutes you can save yourself a lot of issues later on.

Signs of Engine Strain

An exhaust pipe on a white car

In most cars, the part of the exhaust system which connects to the engine will be beneath or close to your feet when you sit on the passenger side of the vehicle. Leaks cause greater strain on exhaust systems, which can make them vibrate violently.

When you sit in the passenger side seat of the car, pay close attention to whether you can feel large vibrations beneath your feet. If you can, there is likely a leak where the exhaust system and the engine meet.

There may be a large leak in your exhaust system which will require you to take the car to a repair shop sooner rather than later to get the issue fixed.

Additional Troubleshooting for Hard to Spot Exhaust Leaks

Foil is a great material to use when you are trying to find the problem in a leaking exhaust system. You can wrap large amounts of foil around different parts of the exhaust while the car is running because the foil will not ignite and catch fire.

The foil will muffle the sound of the exhaust, so pay close attention. When you have wrapped foil over a part of the exhaust where the exhaust noise is quieter, you will have an easier time detecting where the issue is located.

Check the car's valvetrain and head gasket for issues as well. The valve seals in the valvetrain are supposed to prevent engine oil from entering the combustion area. Still, a leaking seal can cause smoke and exhaust pipe oil to leak as well.

The head gasket seals the area between the head and main engine block. If the head gasket is blown, engine coolant from the head can flow into the combustion chambers causing smoke and liquid to leak from the exhaust pipe.

Again, if you determine that your car is having this issue, you should correct it right away to prevent further issues later on.

How Does an Exhaust Leak Affect Performance?

A damaged exhaust can sometimes cause burnt gasses to pass backward and re-enter the combustion chamber which is incredibly harmful to your vehicle. That process will reduce engine efficiency between cycles. You might also experience a reduction in power from the engine if this occurs.

Furthermore, it can also lead to less fuel efficiency. And with how expensive gas is right now, that is obviously ideal for your care or your bank account.

These factors all depend, though, on where the leak is located in the exhaust. The further away from the engine and catalytic converter the leak is, the less chance there is of it doing considerable damage.

If the leak is close to your engine and catalytic converter, though, it could be incredibly serious and necessitate the immediate help of professionals to fix the issue.

While you can drive a car with an exhaust leak, it can be hazardous to your health if carbon monoxide gets inside your car and it can also lead to the car's catalytic converter failing over time as it compensates for the imbalance of oxygen and fuel needed.

Instead, you should try to fix issues as they first arise to prevent bigger issues from sprouting up later on.

By understanding the symptoms of an exhaust leak, you'll be able to know early on if there is an issue with your car. A lot of times these leaks won't be expensive to fix on their own, but fixing the issues leaks cause can be, so you'll want to fix it sooner rather than later.