11 Symptoms of an Exhaust Leak | How to fix an Exhaust Leak?

As we start the car’s engine, all the extra gases and noise from the combustor are sent out through the exhaust system. This system carefully directs unwanted exhaust gases to the back of the vehicle, far from the driver and the passengers. Various damage, rust, and worn-out parts result in an exhaust leak, which affects the overall performance of your vehicle. Due to toxic emissions, exhaust leaks can create some health issues and can be the reason for a dirty environment. This article mainly describes the exhaust leak causes, symptoms, and how to fix it.

What is an Exhaust Leak?

An exhaust leak is basically an opening, hole, or damage in your exhaust system that results in transporting unwanted toxic gases into the vehicle cabin instead of throwing them out of the vehicle through the rear exhaust pipe.

Exhaust Leak

Engine exhaust contains several toxic gases, including phosphorus, nitrogen oxides, carbon monoxide, and metals like unburned fuel and lead.

An exhaust leak can be lethal if the exhaust system or the ventilation system of the car does not adequately remove the pollutants but accumulates them even more rapidly within the car’s cabin.

The most common symptoms of exhaust leaks are poor fuel economy, bad engine performance, noise, and a damaged catalytic converter.

What Is an Exhaust System?

The exhaust system of your vehicle is a linked arrangement of sensors, connections, pipes, and many other components intended to manage and eliminate exhaust gases produced by the combustion process of the engine.

Exhaust System

The main function of the exhaust system is to efficiently route all the unwanted toxic gases out of your car from the back. Additionally, this system also reduces engine noise and assists in managing exhaust emissions by using a catalytic converter.

Components of Exhaust System

The exhaust system of your vehicle has the below-given symptoms:

  • Exhaust valve and piston: These components of an engine help to push exhaust gases out of the combustor and into the exhaust manifold.
  • Exhaust manifold: The route that a piston takes to reach a catalytic converter.
  • Catalytic converter: Cleans the emissions by converting some toxins into carbon dioxide and water. But still, the emitted gasses are characterized as poisonous gasses.
  • Muffler: It uses to minimize the dismissal of exhaust and combustion noise.
  • Exhaust pipe: Transports the muffler’s cleaner exhaust gases.
  • Tailpipe: This is a part from where the vehicle’s exhaust exits.

Symptoms of an Exhaust Leak

The efficient working of your vehicle’s exhaust system is very important for the efficient working of your vehicle.

As your exhaust system goes bad or leaks, it generates one or more symptoms. Your car may exhibit one of the symptoms listed below as soon as there is an exhaust leak:

  1. Higher engine sound than usual 
  2. Exterior carbon buildup
  3. Clicking or tapping sound
  4. Unusual noise when accelerating
  5. Visible defects
  6. Poor fuel efficiency
  7. Unusual odor
  8. Vibrating gas pedal
  9. Failed emission test
  10. Poor engine performance
  11. Check engine light illumination

So, let’s discuss them thoroughly.

1) Unusual Noise When Accelerating

Usually, the accelerator pedal generates a small roaring sound as the driver presses the accelerator pedal to move the car. This noise is produced when the engine spins its parts to create the required driving power. However, any weird noises that you don’t often hear can be a sign of exhaust leaks.

Unusual Noise When Accelerating

If you are hearing strange noises that you don’t normally hear, this could be an indication that you have exhaust fumes leaking from the system somewhere. Here, you should be able to distinguish between noises emanating from your engine and those coming from your exhaust.

2) Tapping or Clicking Sound

The clicking sound you hear from your car may also generate due to a leak in the exhaust manifold. Usually, this sound becomes louder when you start a cold engine. This sound may stop with time when the engine gets heated and the exhaust manifold expands.

Clicking or Tapping Sound, symptoms of exhaust leak

3) Higher Engine Noise

The higher engine noise than usual is one of the major signs of an exhaust leak. There are around two mufflers in your car that help in reducing the engine sound.

Higher Engine Sound due to exhaust leak

If your exhaust system leaks just before the vehicle mufflers, then your mufflers cannot reduce or silence the engine sound. That is because the sound waves fail to reach the muffler and go directly out of the car. Due to this, you will notice the higher engine noise, whose intensity depends on how bad the damage is.

4) Vibrating Gas Pedal

You may feel vibrations in your feet after pressing the gas pedal of your car. These vibrations may be due to exhaust leaks. The intensity of these vibrations increases with the increase in the gas leak.

Vibrating Gas Pedal due to exhaust leak

In case of exhaust leaks, you may also sense vibrations in your steering wheel and floorboards. The vibration will ultimately reach a level where it is audible throughout the entire cabin.

5) Unusual Odor

Carbon monoxide has a strong odor, and if there is an exhaust leak, the car driver and passenger will smell that strong odor inside or outside the car. This gas is dangerous to breathe, so if you notice any kind of odor, get out of your car as soon as possible.

Unusual Odor

In such a condition, taking your car to the nearest service center and running a proper diagnostic to fix this issue is recommended. Do not forget to open the windows of your car in this situation because carbon monoxide can be deadly.

6) High Fuel Consumption

The O2 sensors show the fuel-air ratio of your car. This sensor measures the fuel-air mixture as burning rich or lean and determines the correct air-to-fuel balance.

Poor fuel economy

The O2 sensor is installed in the exhaust system, and the leak before this sensor can make your car run lean.

The powertrain control module (PCM) of your vehicle will be unable to read the amount of oxygen entering and exiting the oxygen sensor valves due to a leak in the exhaust system. That eventually may lead to burning more fuel than usual.

Read More: Working of O2 Sensor

7) Poor Engine Performance

Continuous exhaust flow is necessary for an engine to operate at its best. The car’s back power can drop due to the exhaust leak, resulting in slow acceleration. This loss of power or acceleration can cause serious events.

Engine Performance reduction due to bad DPFE Sensor

8) Check Engine light illumination

The O2 sensors on the exhaust system of your vehicle measure the escaping fuel mixture from the engine and the performance of the catalytic converter.

check engine light

As your exhaust system leaks just before the O2 sensor, then your O2 will be unable to measure the precise readings, and it will deliver wrong readings to the PCM. When your PCM detects an issue within the exhaust system, it instantly triggers the trouble code and illuminates the check engine light.

Read More: Causes of Check Engine Light Flashing

9) Failed Emission Test

In most countries, you must pass the emission test once a year in order to pass the car inspection process. With the leakage in your exhaust system, your car will not be able to pass this emission test.

Failed Emissions Test

A leak before the oxygen sensor will show wrong air-fuel mixture readings, and a leak after the oxygen sensor will show a lean mixture. Hence, your car may fail the test if the size of the leak is a little larger.

10) Visible Defects

The nuts, studs, or screws anchoring the exhaust manifold to the cylinder head may rust and break with time, leading to a leak. If your exhaust manifold is distorted, the bolts may damage or break.

Additionally, burned parts and black streaks around the site of the leak indicate that the exhaust manifold is leaking. During the visual check, cracks in the exhaust manifold might be discovered.

11) Exterior Carbon Buildup

Black areas should be on your radar while you look for the leak’s origin and location. Carbon particles may accumulate around the leak area during an exhaust leak.

Exterior Carbon Buildup

Read More: Symptoms and Causes of Bad EGR Valve

Causes of an Exhaust Leak

Your exhaust system may leak due to multiple reasons. However, the following are the major causes of an exhaust leak:

  1. Corrosion
  2. Damaged gaskets
  3. Physical impacts
  4. Age of the exhaust system
  5. Poor welds
  6. Driving conditions
1) Corrosion

The exhaust of the car is placed at the very bottom of your car. It experiences extremes of heat and cold, rain and snow, is blasted with pebbles, splashed with road asphalt, and bathes in the oil that has leaked from other cars.

Although stainless steel exhaust systems can withstand for a long time, but ultimately rust will start to affect them.

2) Damaged Gaskets

The main function of the gaskets is to stop the leaks. The gaskets are also installed between the engine and exhaust manifold. Over time, gaskets can deteriorate and lead to rough surfaces that invite leaks.

3) Physical Impacts

The exhaust system is installed under the vehicle. Not everybody drives on smooth ground. So, the low-hanging exhaust system might be damaged by bumps and other road conditions. Additionally, it is so low that rogue road debris may frequently hit it.

4) Age of the Exhaust

Everything has to finish. Similarly, one of the most frequent causes of an exhaust leak is an aged exhaust system.

5) Poor Welds

It could cause new leaks if the exhaust system was previously fixed incorrectly.

Poor Welds of the exhaust system

6) Driving Conditions

Driving on difficult roads might subject your exhaust system to vibrations and shocks that can degrade structural elements and cause holes. At the same time, rust and corrosion in exhaust system parts are perfect places for exhaust leaks to form.

How to fix an exhaust leak without welding?

To stop an exhaust leak without welding, use one of the four procedures listed below:

  • Use an aluminum patch
  • Use exhaust tape
  • Use exhaust clamps
  • Use epoxy bond
1) Use an Aluminum patch

An aluminum patch can be used to cover the leaks. Follow the below-given steps to fix an exhaust leak:

  • Inspect the leak and cut the aluminum patch a little larger than the leak area with the help of a heavy-duty scissor.
  • Cut the small patches of the aluminum if the leaks are small, and for larger leaks, it is recommended to wrap the exposed area of the pipe with a large aluminum sheet.
  • Carefully apply the epoxy around the leak, and make sure that you apply a reasonable amount of epoxy that did not drop into the exhaust pipe.
  • Now place the aluminum patch on the leak or wrap the whole pipe with it.
  • Apply the epoxy at the edges of the patch with the help of a wooden dowel.
  • Hold the aluminum sheet with the help of clamps if you have wrapped it around the pipe.
2) Exhaust Tape

Exhaust tape is the best fix for large leaks.

  • Simply wrap the tape around the area of the leak, leaving a little extra at the beginning and end points.
  • Apply this tape twice for better results.

There are various exhaust tapes, and their methods of application can be different. So, do not forget to read the instructions from their packet before applying the tape.

3) Exhaust Clamp

A small or medium leak can be covered with the help of the exhaust clamps.

  • Wrap the clamp around the hole.
  • Tighten that clamp with the help of bolts to avoid further leakage.
4) Epoxy Bond

In the case of small leaks, direct epoxy can be applied to seal the holes or cracks.

  • Clean the leak area.
  • Make a homogeneous mixture of the epoxy by mixing it properly.
  • Now apply this epoxy mixture to the leak.
  • A wooden dowel can be used for the application of epoxy bonds.

Exhaust Leak Repair Cost

The cost of repairing an exhaust leak differs depending on the leak’s nature and labor cost. The typical repair or fixing cost of an exhaust leak is between $80 and $820.

The table below illustrates the average repair costs for exhaust leaks. These rates include both labor and parts costs.

Front exhaust pipe replacement$130 to $620
Replacement of Catback Exhaust$140 to $610
Whole exhaust pipe replacement$285 to $1230
Exhaust braided flex pipe$85 to $320
Exhaust Joint replacement$25 to $210
Welding of Exhaust Pipes$20 to $130
Catalytic Converter replacement$380 to $1610

FAQ Section

What does an exhaust system do?

The basic functions of an exhaust system are as follows:

  • To direct the exhaust gases away from the driver and passengers.
  • Silent the sounds generated by the engine’s internal combustion process.
  • “Clean” the exhaust gases of dangerous gases.

Does an exhaust leak affect gas mileage?

Leakage in an exhaust system impacts not only the driver and passengers’ health but also the engine efficiency and fuel consumption rate. An exhaust system leak affects the pressure inside the exhaust system, which results in lowering fuel economy and increasing pollutants.

Can I drive with an Exhaust Leak?

Driving a car with an exhaust leak is not encouraged since it is hazardous to either you or the environment. There is also a chance of catching fire in a very unfortunate situation. Here, the car’s safety depends on the reason that is causing the exhaust leak. As previously said, exhaust gases may be dangerous if inhaled over an extended period. Sometimes the exhaust fumes may ignite the fuel pipe. If the exhaust pipe is placed in the wrong place, it may help the car catch fire easily.

How does an exhaust leak sound?

An increase in engine noise is a frequent indicator of an exhaust leak. Keep an eye out for a loud rumbling, particularly while racing. You will notice periodic popping or hissing sounds.

How long can I drive with an exhaust leak?

The answer to this question is “as long as you live.” But still, the exhaust leak is deadly. It is recommended to open all the windows of your car while driving to the service center during an exhaust leak.

Would an exhaust leak result in a code?

The triggering of the code depends on the location of the leak. If the leak impacts the oxygen levels, the PCM of your car will instantly trigger the DTC code.

Does an exhaust leak influence performance?

Yes, the engine performance can be affected by an exhaust leak. When you press the gas pedal, you may realize that your car lacks its normal power. If the exhaust leak is not repaired, your car will continue to lose power.

Is JB Weld suitable for exhaust leaks?

JB Weld is a good solution for repairing an exhaust or muffler leak. ExhaustWeld Total Exhaust Repair Wrap is a high-strength fiberglass sheet coated with a specially developed resin for high-temperature fixes.

What issues might a leaking exhaust manifold cause?

With a leaking exhaust manifold, the gas will not filter properly and enter the environment as a toxin. As a result, you may notice an unusual odor coming from the engine compartment. Leaks can result in the overall power reduction of your car.

Can an exhaust leak damage the engine?

Sometimes, a leak at any specific place can result in engine damage. Throwing away toxins is very important and can save you from several injuries.

What does an exhaust leak affect?

  1. Check engine light illumination
  2. Increased engine noise
  3. A reduction in the fuel economy
  4. An increase in the emission rate of the exhaust gases
  5. A reduction in the engine performance

What are the signs of an exhaust leak?

  1. Higher engine sound than usual 
  2. Check engine light illumination
  3. Exterior carbon buildup
  4. Clicking or tapping sound
  5. Visible defects
  6. Vibrating gas pedal
  7. Poor fuel efficiency
  8. Unusual odor
  9. Failed emission test
  10. Unusual noise when accelerating
  11. Poor engine performance
Read More

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