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Summary
  • The exhaust system is responsible for routing exhaust gases away from the engine and directing them towards the tailpipe.
  • The system consists of an exhaust manifold, catalytic converter, O2 sensors, exhaust pipes, a muffler, a resonator, a tailpipe, and other miscellaneous components (e.g. gaskets, heat shields, and hangers).
  • The leaking exhaust system can expose you to high amounts of carbon monoxide.
  • An obstructed exhaust system can also create back pressure, effectively choking the engine and resulting in a series of performance issues.

The exhaust system is tucked away underneath your vehicle, out of sight and out of mind, making it easy to ignore. You may not even know which parts make up the exhaust system—but now’s the time to learn.

By becoming acquainted with the various exhaust system components, such as the muffler and catalytic converter, you’ll be more in tune with your car. You’ll also be better prepared to talk to your mechanic or select parts for repair if any problems should arise.

Car Exhaust System Components

Simplified Automotive Exhaust System Diagram showing different components
A typical exhaust system diagram with basic exhaust system parts 

The exhaust system routes exhaust gases away from the engine and out the vehicle’s tailpipe. A typical modern exhaust system contains the following components:

Exhaust Manifold

Exhaust gases leaving the engine first travel through the exhaust manifold. The manifold collects the exhaust gases from the individual ports in the engine’s cylinder head, then routes those gases to the rest of the exhaust system.

Engines with a ‘V’ or flat configuration have two exhaust manifolds (one for each bank of cylinders), whereas inline or straight engines have just one manifold.

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exhaust manifold
The exhaust manifold collects the exhaust gases from the individual ports in the engine’s cylinder head, then routes those gases to the rest of the exhaust system.

Catalytic Converter

The catalytic converter is an emissions control device that converts harmful exhaust gases into water, carbon dioxide, and nitrogen. Some catalytic converters are integrated into the exhaust manifold, whereas others are attached to the vehicle’s exhaust pipe. It’s also worth noting that some cars have just one catalytic converter, while others have as many as four.

catalytic converter
The catalytic converter is an emissions control device that converts harmful exhaust gases into water, carbon dioxide, and nitrogen.

Oxygen Sensors

Oxygen sensors measure the amount of oxygen (or the concentration of combustibles) in the exhaust gases leaving the engine.

Modern vehicles have both upstream and downstream oxygen sensors. Upstream oxygen sensors are located before the catalytic converter, while downstream sensors are located after the converter.

The engine computer, which is often referred to as the powertrain control module (PCM), uses data from the upstream oxygen sensor to regulate the engine’s fuel mixture. Meanwhile, the PCM primarily uses the signal from the downstream oxygen sensor for monitoring the health of the catalytic converter.

oxygen sensor
Oxygen sensors measure the amount of oxygen (or the concentration of combustibles) in the exhaust gases leaving the engine.

Exhaust Pipes

Various exhaust pipes connect the parts of the exhaust system together. The pipes are often made from aluminized or stainless steel to protect against rust and corrosion.

exhaust pipe
The exhaust pipes are often made from aluminized or stainless steel to protect against rust and corrosion.

Muffler and Resonator

As its name implies, the muffler reduces or “muffles” the noise created by the engine. The exhaust system also has a resonator, which cancels out engine noises of specific frequencies.

muffler and resonator
The muffler reduces or “muffles” the noise created by the engine while the resonator cancels out engine noises of specific frequencies.

Tailpipe

The tailpipe is the final link in the exhaust system—it routes the exhaust gases, which have been cleaned up by the catalytic converter, away from the vehicle and into the atmosphere.

tail pipe
The tailpipe routes the exhaust gases away from the vehicle and into the atmosphere.

Miscellaneous Exhaust System Components (Gaskets, Heat Shields, and Hangers)

Many people forget about the miscellaneous bits and pieces found throughout the exhaust system. For example, there are gaskets that seal the individual exhaust system components to one another.

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There are also heat shields that protect the vehicle—and objects directly beneath it—against the heat from the exhaust system. Plus, there are hangers that serve as mounting points for the various exhaust components.

exhaust system heat shield
Many people forget about the miscellaneous bits and pieces found throughout the exhaust system such as the gaskets and heat shields.

Common Exhaust System Problems

Like any part of your vehicle, the exhaust system can eventually have issues. The most common problems include:

Leaks

Over time, the various components found within the exhaust system can develop leaks. An exhaust system leak is a serious problem because it can expose you to deadly carbon monoxide. Furthermore, a leaking exhaust system can cause the oxygen sensors to interpret a false lean condition, potentially leading to engine performance problems and an illuminated check engine light.

Obstruction

Parts of the exhaust system can become obstructed due to impact damage or upstream engine problems. When the system becomes clogged, it creates excessive back pressure, effectively choking the engine. As a result, the vehicle may exhibit problems, such as lack of acceleration, hard starting, and an illuminated check engine light.

Loose Components

The heat shields in an exhaust system can become loose due to impact damage or missing fasteners. When this happens, you’ll likely hear a metallic rattling noise coming from the undercarriage.

Also, the exhaust hangers can become worn, allowing the exhaust system components to move around and cause clunking or banging noises.

Where To Buy Parts For Your Exhaust System

There’s no doubt that the exhaust system is essential to your vehicle, and keeping all its parts in tip-top shape is essential for smooth, clean driving. If you find any leaks, obstructions, or loose components among its parts, it might be time for a change. The last thing you want is for these issues to affect your vehicle’s emissions. Luckily, getting parts for your exhaust system is easy at CarParts.com.

You can find a variety of exhaust system components at CarParts.com, from oxygen sensors to catalytic converters and more. It takes just a few clicks to place an order through our convenient and secure checkout. Simply find the parts you need, double-check that they fit your vehicle, and proceed to checkout. If you have any questions, you can contact our friendly and helpful customer service team, who offer round-the-clock support.

See also  Emission Control Systems

Place your order for new and quality exhaust system components, including exhaust pipes and more, at CarParts.com today.

Products Mentioned in this Guide

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Replacement – Passenger Side Exhaust Manifold, With Heat Shield and Gasket
, Exhaust System Parts 101: The Basics (Diagram Included)
$56.99 Price and rating may change from the time content is published.
DriveWire – Oxygen Sensor, 4-Wire, Heated
, Exhaust System Parts 101: The Basics (Diagram Included)
$51.99 Price and rating may change from the time content is published.
Evan Fischer® – Muffler
, Exhaust System Parts 101: The Basics (Diagram Included)
$142.08 Price and rating may change from the time content is published.
Evan Fischer® – Center Resonator, Aluminized Steel
, Exhaust System Parts 101: The Basics (Diagram Included)
$76.99 Price and rating may change from the time content is published.
Evan Fischer® – Tail Pipe, Natural, Stainless Steel
, Exhaust System Parts 101: The Basics (Diagram Included)
$44.99 Price and rating may change from the time content is published.
About The Author
Written By Automotive Subject Matter Expert at CarParts.com

Mia Bevacqua has over 14 years of experience in the auto industry and holds a bachelor’s degree in Advanced Automotive Systems. Certifications include ASE Master Automobile Technician, Master Medium/Heavy Truck Technician, L1, L2, L3, and L4 Advanced Level Specialist. Mia loves fixer-upper oddballs, like her 1987 Cavalier Z-24 and 1998 Astro Van AWD.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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James Arnone

Can car over heat from back pressure from clogged cat converter

CarParts.com

Hello James,

Yes, it’s possible for a clogged cat to restrict the exhaust, creating excessive backpressure and heat that backs up into the engine.

-Mia, Chief Mechanic @ CarParts.com

Jessica lemere

I have blue smoke coming out my Exhaust and I’m burning threw oil within a WEEK with zero leaks with a P0420 code. I have a 2017 Hyundai Accent. Any suggestions.

Hello,

It sounds like you have an internal engine concern (worn rings and/or scored cylinder walls) resulting in oil consumption and smoke from the exhaust. The catalytic converter has likely been poisoned as a result of oil consumption.

MNeves

This article is of great value. Thank you for making this available.

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