Exhaust Leak Symptoms and How to Deal With Them

Exhaust leak symptoms

The exhaust system is responsible for making car emissions less harmful before they are moved to the tailpipe. If the exhaust system is damaged or when it is leaking, it produces carbon monoxide, which is poisonous to human beings. The gas emissions are invisible and odorless, and thus, you may not notice or see them. It is, therefore, essential to know the exhaust leak symptoms and their causes.

Exhaust leak may cause a lot of problems on top of making the vehicle have weird noises. The carbon dioxide may cause fatal risks to passengers when it finds its way to the passengers’ cabin. Apart from that, it may affect the car’s gas mileage. Various indicators will help you know that your exhaust is leaking. This article will explain the causes and symptoms of an exhaust leak, how to find the leak and the way to fix it.

Exhaust Leak Causes

It is essential to know the causes of the leaks for easy exhaust leak detection. A vehicle has two manifolds. There is an exhaust manifold and an intake manifold. They are both very important, but the one most likely to experience problems is the exhaust manifold. The main task of the exhaust manifold is the pass gasses from each of the car cylinders to the exhaust pipe.

Manifolds are made of either a one-piece of cast iron with ports or channels built into it or several pipes tied together. When the exhaust manifold has a crack, they cause exhaust leaks. This is because they are subjected to intense heat, which results in contraction and expansion. When they heat up, the metal expands and later contracts when it cools down. This will, in time, lead to manifold fatigue, thus developing cracks. When the manifold has cracks, you will start to notice exhaust leak symptoms.

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Another place where the leakage can come from is from the exhaust manifold gasket. The gasket is located in the middle of the engine block and the manifold. It is made to seal the small gap between the engine block and the manifold. The gasket is also subjected to heat and thus also goes through contraction and expansion. The gasket will fail eventually due to wear and tear and begin to cause exhaust leak.

It is crucial to check the parts regularly to avoid exhaust leak effects. When there is a leakage in the exhaust system, hot exhaust gasses are emitted under the hood instead of going down via the exhaust pipe. This can cause damages to the plastic components found in the engine bay.

The exhaust fumes can get to the car’s cabin, thus becoming a health hazard to the people riding in the vehicle. The leaks may also affect the performance of the engine. When the exhaust manifold is leaking, the backpressure supposed to be in the exhaust system will not be correct, thus reducing the engine power. This may result in sputtering and other problems.

Exhaust Leak Symptoms

There are several ways through which you can know that your car has an exhaust leak. You need to be very attentive to note the changes occurring in your vehicle. Below are six symptoms of exhaust leak before the o2 sensor:

1.   Vibrations

A car will start vibrating even when it has a small leak in the exhaust system. The vibrations will become bigger as the leak increases.  The vibrations mainly start at the gas pedal. You will later feel the vibrations on the steering when you leave the problem unsolved. When the exhaust leak continues, the vibrations will move to the floorboards, and they will later be felt in the whole cabin.

2.   Popping and Hissing Noises from the Engine

Another most common clue is an exhaust leak sound when accelerating. In case you hear some popping or hissing noise when the engine is running, then there is a problem with the exhaust system. This leak could have resulted from a damaged gasket, which separates the exhaust manifold and the engine block. This noise will be louder when you accelerate the vehicle or during a cold start.

3.   Bad Fuel Efficiency

Another way to detect leakage on the exhaust system is when your vehicle starts to use more gas than before. The leak reduces the engine power and acceleration, thus lowering its fuel efficiency. When there is a leak in the exhaust system, the engine is forced to work harder and thus requiring more fuel. Exhaust leak effects will be more if you do not get the problem fixed soon.

4.   Unusual Odor

A burning odor is another of the turbo exhaust leak symptoms. Carbon monoxide is odorless and colorless, but other exhaust fumes have odors. A leaky exhaust system may result in a strange burning smell in the car cabin. When the exhaust manifold fails, the heat from the gasses could make the plastic components under the hood to burn, thus the burning smell. It can also release some smoke when it worsens, which is quite risky to the people in the vehicle. Get your car serviced by an automobile mechanic immediately you notice the smell.

5.   Tough Acceleration

Problems with your exhaust will affect your engine’s performance. It will make it hard for you to accelerate as quickly or as well as before. You will also not get the same power when accelerating, and it will continue to worsen if the exhaust leak is not taken care of. You will also hear some noises when you accelerate your vehicle. One should be able to differentiate between the exhaust sounds and engine sounds. 

6.   Small Leaks

During the thermal contraction and expansion, which occurs when you start an engine, the exhaust manifold gasket is subjected to stress. After some time, you may notice small leaks, and they may become bigger as the days go by.  This may be a sign that there is a problem with the exhaust system. The leaks may be running from a crack on the exhaust manifold or at the gasket. When inspecting the small leaks, start from the engine going back to the tailpipe. The best place you need to check is where the cylinder head and the exhaust manifold meets.

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How to Find Exhaust Leak

If you are suspicious that there is a leak in your exhaust system, the other step is to find where exactly it is. Before you start inspecting the exhaust system, you need to do some preparations. It is always advisable for you to start checking leaks on pipe connections clamped, bolted, or welded.

Some areas in an exhaust system are more prone to leaks than others. However, do not ignore other areas since leaks can also come from the most unexpected places. If you are not a professional in this, you can get an expert to do it for you. Begin by jacking up the vehicle so that you can have a good view of the exhaust system under the car. Below are ways you can use to find where the exhaust leak is coming from.

Use a Vacuum Cleaner

When using a vacuum cleaner, ensure that the vehicle is cooled down. It is crucial to concentrate more on joints and flexible parts of the system since they are prone to leaks. After finishing the test, remember to detach the vacuum cleaner before you start your car.

  • Connect the pipe of your vacuum cleaner in your car’s tailpipe
  • Switch the vacuum cleaner on
  • Put some water in a spray bottle. The best way is to find an exhaust leak with soapy water
  • Spray the water or soapy water on the entire exhaust system
  • If you see some bubbling, then it means that that is where the leak is

Using a Stethoscope

The best way to use a stethoscope is still suing a vacuum cleaner and when the vehicle is cool.

  • Connect the vacuum cleaners pipe in the exhaust pipe
  • Switch on the vacuum cleaner
  • Jam the end of the stethoscope with a small flexible tube
  • Bring the open end of the stethoscope as close to the exhaust system as you can
  • Pay special attention to flexible sections and joints of the exhaust system
  • Listen for leaks through the stethoscope
  • When you move the stethoscope over a leak, you hear the exhaust leak sound ticking
  • Confirm the leak by pressing the area with your finger to hear if it will disappear

Clogging the Exhaust System

This method is aimed to make the exhaust leak worse temporarily by creating backpressure so that it can be easy to find. These are the steps to follow:

  • Take a rag or clothing and clog the exhaust pipe
  • Start your car and let it run when the rug is still stuffed in
  • The leak will become louder due to the backpressure
  • Spray the area where the leak is with soapy water
  • Bubbles will form where the leak is, and that is where the exhaust leak is coming from

If you find leaks on the exhaust system, the other step is to fix them. However, if the leaks in the system are too much, you can patch them with good welds or replace the whole system. Remember that the car needs to be cool before taking the process of finding exhaust leaks so as to avoid getting burnt.

How to Fix Exhaust Leak

There are various ways of fixing exhaust leaks, depending on its situation and point of the leak. Some of the most common areas exhaust leaks occur on rusted areas, welds and joints of the pipe. Once you notice an exhaust leak, you should fix it as soon as possible to avoid further exhaust leak effects. This is step by step guidelines on fixing exhaust leaks:

Exhaust System

Using a Repair Epoxy or Exhaust Tape

These two methods are ideal to use if you want to patch an exhaust leak. If it is just a tiny crack or a small pinhole, seal it with epoxy or exhaust tape instead of patching. Patching is better used on larger holes. Follow the guideline below:

  • Turn off the vehicle and wait for it to cool
  • If the car is cool, clean the area where the leak is using a steel brush
  • Ensure that you have a protective ware for your eyes to avoid dirt from getting into your eyes during the scrubbing
  • Rough up the area, you are going to repair it with sandpaper. The sandpaper will assist in removing any bits of dirt. It will also create small grooves, which will make it easy for tape and epoxy to stick on the metal.
  • Wipe the area you have sanded and scrubbed with acetone. In case you do not have acetone, you can wipe the area with nail polish remover.

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a.    Using an Exhaust Tape

After going through the above steps and you decide to use an exhaust leak repair tape follow the steps below:

  • Wrap the area where the leak is all round with an exhaust tape
  • Wrap the point with a minimum of two layers of exhaust tape
  • Ensure that the tape is wrapped a few inches on both sides of the leak to make it more stable

b.    Using Epoxy

If you decide to use epoxy, ensure that you go through the cleaning process, we discussed above first. The drying period of the epoxy depends on the brand you use. It is thus crucial to use a high-quality epoxy for the process. After cleaning the area, follow these steps:

  • Mix the two parts of the epoxy using a dowel
  • The epoxy will start binding right away so make the process fast
  • Paste the epoxy on the crack or hole
  • Spread it around the leak on the pipe using a dowel
  • Leave a generous epoxy layer over the point of leakage
  • You can wrap the area with an exhaust tape

Repairing the Leak Using a Patch

A patch is recommendable for repairing a larger exhaust leak. There are several patch kits or Exhaust Selants on auto parts store which you can use in the procedure. You can also patch the exhaust leak with aluminium patches. This is how to fix an exhaust manifold leak:

  • Scrub and clean the surface around the exhaust leak
  • Measure the size of the hole causing the leakage
  • Cut a patch an inch or half an inch larger than the hole
  • Wear some gloves when cutting the aluminium to prevent getting cuts on your fingers from its sharp edges
  • Place the wrap on the hole to see if it fits well
  • If the shape and the size of the patch are perfect, mix up epoxy
  • Cover the area of the leak with epoxy
  • Place the patch on the epoxy over the hole. Epoxy helps you hold the patch
  • Ensure that the leak is covered entirely
  • Apply more epoxy on the edges of the patch. It helps to create a more solid seal and prevent future leakages

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Final Words

When you notice any of the exhaust symptoms that we have discussed above, then it means that there is a problem with your exhaust system. However, even if you fail to notice any, there may still be leaks. Have the exhaust system checks regularly to avoid exhaust leak effects in the future. If the vehicle is more than five years, one is advised to take the exhaust system for inspection one time in a year. An inspection will help you discover minor damages and loose parts in the system, which could be repaired before they become worse.

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