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How to Clear a Clogged Exhaust (Step-by-Step)

Updated: Jan 8

A clogged exhaust can be a nuisance for any vehicle owner. Not only does it affect the performance of your vehicle, but it can also be dangerous if left unchecked.

In this article, we will explain how to clear a clogged exhaust, including step-by-step instructions for deep cleaning and unclogging the catalytic converter and muffler.


Table of Contents:

exhaust system from underneath a car

Parts of an Exhaust System

Before we dive into the details of how to clear a clogged exhaust, it's important to understand the different parts of the exhaust system.

The exhaust system consists of several components that work together to remove harmful gases from the engine and reduce noise levels. Some of the main parts of the exhaust system include the following.

  • Exhaust manifold: This is the exhaust component that connects the engine to the rest of the exhaust system.

  • Catalytic converter: This component reduces harmful emissions by converting them into less harmful gases.

  • Muffler: The muffler is an exhaust component that helps reduce noise levels.

  • Resonator: This is a smaller component that helps reduce noise levels and can be found in some vehicles.

  • Exhaust pipe: The exhaust pipes are responsible for directing the exhaust gases out of the vehicle.

What Causes a Blocked Exhaust?

There are several factors that can lead to a blocked exhaust. Some common causes include the following.

  • Accumulation of dirt and debris: Over time, dirt and debris can accumulate in the exhaust system, leading to a blockage. A clean air filter will prevent any debris from entering the engine and exhaust system.

  • Carbon build-up: Carbon deposits can build up in the exhaust system, particularly in the catalytic converter, leading to a blockage. Using a carbon build up fuel additive can help reduce and prevent this.

  • Rust: Rust can form in the exhaust system over time, causing a blockage. Higher milage vehicles and those with cheaper exhaust system components will be more susceptible to rust.

  • Damaged components: If any of the components in the exhaust system are damaged, it can lead to a blockage.

What Does a Clogged Exhaust Sound Like?

If you suspect that your exhaust is clogged, there are several signs to look out for. One of the most obvious signs is a change in the sound of the exhaust. A clogged exhaust can sound louder or different than usual. You may also notice a change in the pitch of the exhaust note.

Can a Car Run With a Blocked Exhaust?

It is not recommended to drive a vehicle with a blocked exhaust. A blocked exhaust can cause a variety of problems, including reduced fuel efficiency and performance.

In addition, driving a vehicle with a blocked exhaust can be dangerous as it can lead to carbon monoxide buildup inside the vehicle. Carbon monoxide is a poisonous gas that can be deadly if inhaled.

Clogged Exhaust Symptoms

There are several symptoms to look out for if you suspect that your exhaust is clogged. Some of the most common symptoms of a clogged exhaust system include the following.

  • Burning smell: If you notice a burning smell coming from the exhaust, it could be a sign of a clogged exhaust.

  • Strong smell of fuel: If you notice a strong smell of fuel coming from the exhaust, it could be a sign of a clogged exhaust.

  • Reduced fuel efficiency and performance: A clogged exhaust can affect the performance of your vehicle, leading to reduced fuel efficiency.

  • Louder engine noise: If you notice that the engine is louder than usual, it could be a sign of a clogged exhaust.

  • Check engine light: If the check engine light comes on, it could be a sign of a problem with the exhaust system.

How to Clear a Clogged Exhaust

There are several methods you can use to clear a clogged exhaust. One method is to use an exhaust system cleaner. If using an exhaust system cleaner additive doesn't clear the blocked exhaust, you may have to deep clean the catalytic converter or muffler.

Use an Exhaust System Cleaner

An exhaust system cleaner is a chemical that can help break down and remove blockages in the exhaust system. Here's how to use it.

  1. Ensure your vehicle has enough fuel (at least 15 litres). This is important because the exhaust system cleaner needs to be mixed with the fuel in order to work effectively.

  2. Pour in an exhaust system cleaner additive into your fuel tank. Follow the instructions on the package for the correct amount to use.

  3. Drive your vehicle for 20-30 miles ideally at highway speeds. This will allow the exhaust system cleaner to work its way through the system and help break down any blockages.

How to Deep Clean and Unclog a Catalytic Converter

If the exhaust system cleaner does not clear the blockage, or if you suspect that the catalytic converter is the source of the problem, you may need to deep clean and unclog the catalytic converter. Here's how to do it.

  1. Allow your vehicle and exhaust system to cool down. This is important as the catalytic converter can get very hot and can cause burns if touched while hot.

  2. Disconnect the negative terminal on the battery. This will prevent any electrical accidents while working on the vehicle.

  3. Safely jack up the vehicle. Make sure to use a properly rated hydraulic floor jack and jack stands to support the vehicle and follow all safety instructions. Always put your spare wheel and floor jack under the car and use four certified jack stands.

  4. Soak the bolts holding the catalytic converter and oxygen sensors in place with specialist penetrating WD-40. This will help loosen the bolts and make it easier to remove the catalytic converter.

  5. Remove the oxygen sensors. Be careful not to damage the sensors as they are delicate, you will need