The words muffler and exhaust are often used to mean the same thing.  But are they?  And when we say muffler or exhaust what is it we are really referring to?

A muffler and an exhaust are NOT the same thing.

This is a common misconception.  Most people use muffler or exhaust to refer to the tailpipe sticking out the back of their vehicle; but it is neither.  The muffler and exhaust do their jobs behind the scenes.  Let’s take a look at what they are for:

The Exhaust

The exhaust is really a whole system of components that’s job is to ensure the gasses going into the environment are as clean as they can be.  This system is known as the “exhaust system”.  It’s easy to think of it as the gas controller.


The Muffler

The cylinder just before the tailpipe, the muffler’s job is to reduce or “muffle” the sound that the engine makes.  Ever noticed how these cylinders are often shaped differently on different cars?  This is because different cars can produce different noises and to varying degrees.

It’s easy to think of the muffler as the noise reducer.


Problems caused by the muffler or exhaust system

If you have loud sounds, black smoke or emissions problems then you may have a problem with your muffler or exhaust.  A mechanic will be able to diagnose the problem regardless of whether you get the description right or not.  Understanding the difference between the two however, can help to give you a little more knowledge and confidence when speaking to a mechanic about your car.


Other parts of the exhaust system

You might hear a mechanic mention:

1. The exhaust manifold

Gasses from various engine cylinders are collected in the exhaust manifold before being passed on to the rest of the exhaust system.

2. The catalytic converter

The gasses are passed on to the catalytic converter where it converts harmful gasses into water vapour and carbon dioxide.

Warning – Catalytic converters have been valuable to thieves for their scrap metal value.  It’s not obvious it has been stolen visually because it lies underneath your car.  You can drive without one but you’ll fast run into problems.  Here’s why.


3. The resonator 

This section comes next, helping to reduce vibrations from the engine, improve airflow out of the tailpipe and make for better fuel efficiency.


4. The muffler

The last stage before the gasses exits the tailpipe.  The muffler uses different chambers of pipes with holes in that reduce engine noises.  It also has a role in airflow and resulting fuel efficiency.

Take a look at our useful infographic representation below showing the whole exhaust system, including the muffler, where parts are, what they look like and the step-by-step process that car emissions go through:

Muffler vs Exhaust Infographic

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