Exhaust System

Step by step guide on how an automotive exhaust system works. This article pertains to all gasoline powered vehicles.

Step 1 - Once exhaust gases are generated from an internal combustion engine, the exhaust system is responsible for routing these gases from the engine. The process begins as the exhaust valve opens and releases hot gases into a exhaust manifold which is connected to the cylinder head. An exhaust manifold is bolted to the cylinder head, and is used to gather exhaust gases from the cylinder ports and collected into one location.

Exhaust Manifold

Step 2 - After collecting exhaust gases, the manifold disperses them at the manifold flange connection.

Exhaust Manifold Flange

Step 3 - Then, these gases are collected at the flange as they enter the head pipe which bolts to the manifold flange.

Exhaust System Head Pipe

Step 4 - Exhaust gases then travel to the catalytic converter, which houses the oxygen sensor. There is a primary sensor located on the head pipe, this device is shielded from the body using a heat shield.

Catalytic Converter w/Oxygen Sensor

Step 5 - Once the gases are treated by the catalytic converter and read by the oxygen sensor they are released into the primary transfer pipes.

Primary Transfer Pipes


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2015-01-07)