How To Find An Exhaust Leak With Soapy Water - Vehicle Freak

• Brian Onyango

Updated on April 8, 2024

Exhaust leaks are an inconvenient problem to have because it not only increases the noise generated by the engine but also allow exhaust fumes to enter the cabin.

This is why it’s so important to understand the signs of an exhaust leak, and how to detect and repair a leak yourself. Let’s take a look at how to find the indications of an exhaust leak.

To find an exhaust leak, you’ll need is a spray bottle of soapy water and a way to deliver forced air into the tailpipe. With the air pressurizing the exhaust system, spray soapy water on the exhaust manifold to reveal leaks.

Bubbles in the places you spray soapy water on are a sign that your exhaust is leaking from that location. You don’t have to stop spraying the soapy water when you see bubbles on a single spot as your exhaust may be leaking from more than one position.

Exhaust Leaks

The exhaust system of a motor vehicle is a network of pipes, joints, sensors, and mechanical components that is designed to handle and discharge exhaust gases generated by the combustion process.

Exhaust leaks are therefore a result of holes or cracks that develop in the system, and they can cause a variety of problems.

Causes

Exhaust leaks may occur for several reasons which may include;

• Worn-out parts: Over time, some of the parts in the exhaust system may wear out and break down, resulting in holes and cracks.
• Damage: The exhaust system can also be damaged by objects that may come into contact with it while driving.
• Poor installation: Exhaust leaks can also be caused by poor installation, which may result in loose connections and gaps.
• Failing Gaskets: The gaskets in the exhaust system may also fail over time, causing exhaust leaks.

Signs

Several signs may indicate that your vehicle has an exhaust leak such as;

• Your car’s engine is making strange noises.
• You smell exhaust fumes inside your car.
• Your car’s fuel efficiency has decreased.

Using the Soapy Test Method to Find Exhaust Leaks

The soapy test is a simple and effective way to find exhaust leaks. All you need is a spray bottle of soapy water and a leaf blower or an air compressor.

Here’s how to do it:

1. Spray the soapy water on the suspect areas and connect your leaf blower or air compressor to your exhaust tailpipe.
2. Turn on your leaf blower or air compressor and get a spray bottle. Spray the soapy water over the suspected locations.
3. Bubbles in the places you spray soapy water on are a sign that your exhaust is leaking from that location.

You may have to repeat the process several times to find all of the leaks.

Other Methods of Detecting Exhaust Leaks

Other than using soapy water, there are other ways that you can detect exhaust leaks;

1. Using a Stethoscope

A stethoscope can be used to identify the location of an exhaust leak. Simply place the diaphragm of the stethoscope on different parts of the exhaust system and listen for any unusual noises.

2. Pressure Test

Another way of detecting exhaust leaks is by performing a pressure test on the system. This can be done with a specialized tool that is attached to the exhaust pipe and inflated. If there are any holes or cracks in the system, the pressure will escape from those areas.

3. Oscilloscope Test

This is a more sophisticated method of detecting exhaust leaks and is usually done by mechanics. An oscilloscope is attached to the exhaust pipe and the engine is started. The oscilloscope will pick up any changes in pressure in the system which indicate a leak.

4. Checking for Backpressure

Backpressure is a condition in which the exhaust gases are not able to flow freely through the system. This can be caused by several things, including an exhaust leak.

To check for backpressure, a specialized tool is attached to the exhaust pipe and a pressure reading is taken. If there is an excessive amount of pressure, it may be an indication of an exhaust leak.

5. Performing a Visual Inspection

A visual inspection of the exhaust system can also be done to look for any holes or cracks. This is usually done with the help of a flashlight to check for cracks on the exhaust pipe.

How Do You Fix Exhaust Leaks

Exhaust leaks can be fixed in several ways, depending on the severity of the leak. Some of the ways of fixing exhaust leaks may include;

1. Using Sealant

The most common is to use an exhaust sealant. Tapes and putties can also be used. Sadly these are only temporary fixes that will, later on, need to be addressed.

2. Tightening

If the exhaust leak is due to loose connections, then simply tightening the bolts and joints may be enough to stop the leak.

3. Welding

When the exhaust leak is due to a hole you can also weld the cracked area. It is just a sealant for specific areas. It is a more extensive repair and will need to be done by a professional.

Frequently Asked Questions

Is It Okay to Drive With an Exhaust Leak?

It is not advisable to drive with an exhaust leak as it can be dangerous. Exhaust fumes contain carbon monoxide, which is a poisonous gas. If there is an exhaust leak, the fumes can enter the car and cause serious health problems.

Can an Exhaust Leak Cause My Car to Overheat?

Yes, an exhaust leak can cause your car to overheat. The exhaust system is responsible for carrying away the hot gases produced by the engine. If there is a leak, these gases can escape and cause the engine to overheat.

My Car Failed Its Emissions Test, Does That Mean I Have an Exhaust Leak?

Not necessarily. There are many reasons why a car may fail an emissions test. An exhaust leak is one of them, but it is not the only reason.

How Much Does It Cost to Fix an Exhaust Leak?

The cost to fix an exhaust leak depends on the severity of the leak and the method used to fix it. A simple sealant can cost as little as $20, while a more complex repair can cost hundreds of dollars.

Will an Exhaust Leak Throw a Code?

An exhaust leak will not necessarily throw a code. However, it might depend on the location of the leak and whether the leak is severe enough, it can cause the engine to run lean, which will trigger a check engine light.

What Does an Exhaust Leak Smell Like?

An exhaust leak usually smells like sulfur or rotten eggs. This is because the exhaust fumes contain sulfur dioxide, which has a distinct smell.

Conclusion

You’ll need a spray bottle of soapy water and a leaf blower, an air compressor with gloves and tapes, or anything that will send in the air into the exhaust system. Spray the soapy water on the suspect areas and connect your leaf blower to your exhaust tailpipe.

It can be secured with tape. Turn on your leaf blower or air compressor, whichever you’re using. Get a spray bottle and spray the soapy water over the suspected locations.

Bubbles in the areas you spray soapy water on are a clear indication that your exhaust is leaking from there. When you see bubbles in a single location, don’t worry about stopping spraying the soapy water; your exhaust may be leaking from more than one place.

If you’re over-spraying, don’t be concerned about how much of the soapy water you can pour on a car.

An exhaust leak is a serious problem and should be fixed as soon as possible. If you think you have an exhaust leak, the best course of action is to take your car to a mechanic and have them diagnose the problem.

Here are some other articles to read:

Water Is Leaking From the Muffler, But Not From the Tailpipe (Causes and Fixes)

How Much Does It Cost to Fix an Exhaust Leak?

Can An Exhaust Leak Cause A Misfire?