How To Find An Exhaust Leak In 7 Simple Steps

Does your car make a lot of noise when you start it? Recently, my sister’s car started sounding louder than normal, but she was not sure what the issue was.

I explained to her that it was an exhaust leak, and she asked me how to find an exhaust leak. I was surprised that she did not know, so I set out to help her.

Once the leak was repaired, I realized that there are probably a lot of others who would be in a similar situation, so I created this guide to help you find any leaks or issues that your exhaust may have.

What You Need

There are different ways to find a leak in your exhaust, but I find that the vacuum method is the simplest way to find a leak without starting your vehicle or doing a lot of excess work.

If you are having trouble feeling the air coming out of your exhaust system with this method, there is a more visible option that uses smoke instead of air. This method works just as well, but it is a bit more of a process, so I prefer the vacuum method.

If you do not have a vacuum, then the third method that I find works well is simply using a rag and the exhaust from the vehicle. The reason that this is not my favorite method is that it requires you to look at the exhaust system closely when the engine is running.

I chose to detail the vacuum method here because it is simple and it does not take more than one person to find the leak; making it ideal for many of you.

Vacuum Method:

A car jack
Two jack stands
A vacuum
Duct tape
An extension cord
A funnel
A length of flexible tubing

Step By Step Instructions

#1 Jack Up The Car

Before you do anything, you will want to jack up the car and secure it with two jack stands so that you can inspect the exhaust system properly and get to all of the areas under the car that are hard to see.

Make sure that the car is secured with the jack stands on both sides of the jack.

#2 Inspect the Exhaust

If you are not sure where the leak in your exhaust is, then the next thing that you need to do is visually inspect it to see if there is an obvious hole in the exhaust system.

One way to notice a leak is to look for soot that may be surrounding the crack or the hole.

You may be able to tell whether the excess noise is coming from the front of the car or one of the pipes that are beneath the vehicle, so start in that area.

#3 Hook Up the Vacuum

If you cannot find the leak, then it is time to hook the vacuum up to the tailpipe. This is a simple process to complete, but you need to make sure that the seal around the vacuum hose and the tailpipe are secure. Place the vacuum hose into the tailpipe. If for some reason the vacuum hose is larger, the tailpipe can fit inside the hose as well. Once the hose is in place, secure it with duct tape.

#4 Create A Stethoscope

Before you turn the vacuum on, create a stethoscope with the funnel and the length of the hose to help you locate the leak. Make sure that you securely tape the hose to the funnel so that you can easily hear the leak when you go over it. If you have a real stethoscope, it will work as well.

#5 Find The Leak

If you feel the leak is in the front of the car, place the stethoscope that you made to your ear and move the tube across the exhaust system components that are under the hood of your car.

Make sure to thoroughly check all of the joints because they are more likely to form a leak.

When you go over a leak, you will notice a hissing sound in the stethoscope. When you hear this sound, confirm that there is indeed a leak by putting your finger in the same location.

You should be able to feel the air through the hole.

#6 The Search Continues

If you do not find a leak in the hood, don’t forget that the exhaust system goes back the entire length of the car.

We jacked the car up so that you have easy access to the pipes under the vehicle, so climb under there and continue the search with your stethoscope.

I’d suggest starting in front of the catalytic converter because those pipes are more likely to leak than the ones in the rear of the car.

#7 Make The Repairs

Once you have located the leak, all you need to do is make the repairs. It could be an easy welding job, but if you do not have the tools to fix the leak, take it to a mechanic and let them know where the leak is located for quick repairs.

Pro Tips For This Method:

Do not start your car before you begin to look for the leak. The exhaust system can become very hot; in fact, touching it is likely to cause burns. If you recently had your car running, make sure it has plenty of time to cool before you begin your search.
Do not forget to disconnect the vacuum from the tailpipe before you start the engine of your vehicle. That could be a tragic mistake.

Wrapping It Up

Did you enjoy this tutorial? Knowing how to find an exhaust leak is important so that you can prevent a small leak from becoming a hole, so I hope this information was useful to you.

Please share your experiences finding an exhaust leak, and don’t be afraid to share this guide so that others can know what to do when they have a problem locating an exhaust leak.