How to Find and Fix an Exhaust Leak In the Car

how to fix an exhaust leak

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Your car’s exhaust system is responsible for emitting exhaust fumes away from your car’s engine and compartment. When it is in good condition, it converts toxic fumes to cleaner fumes. It emits less noise from engines.  However, Exhaust leaks may lead to very serious problems.

How do you know if you have an exhaust leak?  You will notice the signs of exhaust leaks, It is good for you to find and fix an exhaust leak in your car.


How Does the Exhaust System Work?

Exhaust_manifold

The exhaust system is the hottest part of a vehicle. When the combustion process from the engine takes place, the exhaust valves open. These valves make way for exhaust gases and sound waves in the exhaust system. The gases formed into vapors are carbon monoxide, sulfur dioxide, and hydrocarbons. These gases are extremely harmful and turn the manifold extremely hot. The manifold could hold a temperature of up to 1,200 °C.

The manifold is the part of the exhaust system that gathers these fumes with its four-cylinder pipes. Pipes will break down the four cylinders into two for even distribution of the hot gases. The temperature decreases as the fumes flow on the pipes. The temperature decreases to 700 to 800 °C. A single pipe connected to the two exhaust pipes gathers the exhaust fumes.

Joints connect these tubes, sealed by gaskets, to prevent exhaust fumes from escaping. These pipes connect to the catalytic converter. The converter turns the fumes to less harmful vapors.  By this time, the gases become oxygen, carbon monoxide, and nitrogen.

There are oxygen sensors placed in the manifold and this pipe. These oxygen sensors detect the amount of oxygen on the first sensor and the 2nd sensor. 

Both the sound waves and exhaust vapors will travel to another pipe. When the second sensor detects an unreduced amount of oxygen, it will turn the check engine light on. That means that the converter has a problem.

The pipe after the converter will lead to the muffler. The muffler will now reduce the impact of sound waves to make less emission noise. Reduced noise and less harmful gases will travel to the tailpipe out to the air stream. A quiet emission is a sign that your exhaust system is in good condition.

Exhaust muffler

 How to Find an Exhaust Leak

Now you’re on the quest of spotting the leak in your exhaust system. The first thing to do is to listen to the noise. Find out where the noise comes from.

You will need a high jack, a jack stand, gloves, and paper in inspecting your exhaust system. Lift your car securely, start the engine, and listen. If you still can’t find it, run your fingers through the pipes and locate the part where fumes are blowing.

Indications that you have a faulty exhaust system

Exhaust leaks are indications that you have a faulty exhaust system. When there are holes and cracks on any part of the system, the exhaust fumes will escape from the system. Exhaust leaks are dangerous.

Exhaust leaks may lead to the following problems:

1. Carbon monoxide intoxication

The gases, when they come from manifold leaks, are blending toxic gases in their purest form.

These gases flow through your air conditioning system. Inhaling too much of these gases leads to heavy breathing, and worst, gas intoxication.

2. Reduced fuel mileage

Exhaust leaks will require your engine to work more. An engine that works harder needs additional fuel consumption.

3. Poor engine performance

Pressure from the exhaust system defines your engine’s performance. A leak in the exhaust system leads to rumbling and vibrations when you start or accelerate your engine. Sometimes, the engine will fail to start at all.

4. Check engine light indicator

The engine light indicator will turn on when there are exhaust leaks. When this light turns on, your catalytic converter can be failing. As you know, when this light turns on, you have to think twice if it’s still safe to drive.

5. Failed emission test results

You won’t pass emission tests when you have exhaust leaks. For one, the laws, in coordination with EPA, require every vehicle to emit clean air.

Signs of Exhaust Leaks

1. Vibrations

You’ll experience rumbling in your bumper when you start your engine or try to accelerate your engine.

2. Noisy Acceleration

Exhaust leak sounds when accelerating vary from whistling, puffing, to ticking sounds.

3. Frequent fuel top-up

You barely hear noises from your exhaust system when it’s moving. You may notice it when you constantly have low fuel levels.

4. Engine noise

A rattling noise, along with vibrations, comes after you start the engine. The leak may come from a gasket connecting the manifold and engine block.

5. Burning smell

One exhaust manifold leak symptom is when fumes start to get through the compartment. You’ll inhale fumes. The HVAC system sucks them up. These fumes compress inside the cabin.


How to Fix an Exhaust Leak

Fix holes and cracks on pipes

Patching

Fix small holes or cracks with exhaust tapes and epoxy

  1. Scrub off the rust and dirt.
  2. Sand the surface.
  3. Wipe the surface around the leak with acetone.
  4. Roll an exhaust tape around the leak in the pipe.
  5. Seal the wrapped leak with epoxy.

Replacing gasket

Warning!

You may need lubrication to perform this.
Use gloves.
Let the pipes cool down.

Procedures:

  1. Scrub off the rust and dirt.
  2. Remove the bolts and nuts that hold the pipes together using a wrench.
  3. Separate the pipes.
  4. Remove the gasket.
  5. Sand the excess rust and dirt. Be careful not to let dirt get inside the pipes!
  6. Install the new gasket properly.
  7. Fasten the pipes together.
  8. Start the engine.
  9. Inspect the newly installed gasket if it still blows air.

Repairing the manifold

Warning!

Protect your eyes!
Keep away from ignition sources!
Let the manifold cool down.
If you are not confident in welding, let the experts handle this!

Procedures:

  1. Clean the hole or cracked part. Scrub off the dirt and particles.
  2. Heat the affected part with an oxy-acetylene torch. Start with the lowest heat level.
  3. Solder the tip.
  4. Weld with gentle strokes evenly. Do not stay in one part.
  5. Fill the hole or crack completely.
  6. Let it cool before testing.

These are a few ways on how to find and fix an exhaust leak in your car. With accurate diagnosis, you can run your car smoothly without the noise and exhaust leaks.



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About the Author JamesL Davis

James is a certified auto technician specializing in commercial vehicles. With 30 years of experience under his belt, James has encountered almost every type of automotive issue there is! Besides his day job at the repair shop, he is also an amateur race car driver.

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