Exhaust Systems

Automotive exhaust systems are an extremely important safety part of your vehicle and also play a vital role in the performance, fuel economy and operating systems governed by many emission control regulations.

The components that make up an exhaust system vary considerably between manufacturers and country requirements.

Its main purpose is to reduce both the emission and noise pollution created by the normal workings of the engine of your vehicle.

Whilst some components are common to both petrol and diesel systems, others are not and diesel-powered vehicles often require a different approach regarding periodic maintenance and procedures required to keep the system operating.

So what is the main function of an exhaust system?

As your vehicle operates, the internal combustion engine used creates explosions that push the pistons in the engine creating the power we feel when the engine is operational.

This combustion process produces leftover gasses and contaminants that need to be disposed of, this is the role of your vehicles exhaust system components.

Whether it is redirecting gases to be fired again in the engine (EGR valve) or directing the exhaust gasses to the tailpipe, an exhaust system and its components must be in good working order to efficiently carry out its role.

The gasses produced are dangerous to the human body, typically carbon dioxide, carbon monoxide, nitrogen oxides and hydrocarbons. Whilst we can’t see these gasses, we don’t want them entering into the engine compartment or cabin, so one of the main jobs of the exhaust system is to redirect these gasses out the tailpipe located at the rear of the vehicle.

With other components of the exhaust system, in place to reduce both noise and harmful emissions entering the air around us.

With two basic types of fuel systems in use Petrol and Diesel, exhaust systems are designed to suit the different fuel systems and process the leftover gasses and carbons each produces.

Components of a typical vehicles exhaust system

Exhaust Manifold Header

When the exhaust gases leave the cylinder head where the explosions take place, it enters the manifold, designed to gather all these gases so they can be directed away from the engine bay and cabin area.

Sometimes original cast iron manifolds are replaced with extractors to increase exhaust flow and improve engine performance, the principle remains the same.

The Catalytic converter

Its role is to convert the poisonous exhaust gases from the engine into gases that are less harmful to the atmosphere. The nature of what they do and how they operate means they require maintenance and replacement from time to time.

This should always be diagnosed and attended to by a qualified technician, removing a catalytic converter from a system and not replacing it is illegal.

The removal of poisons is its role and when working properly it is very efficient.

The Exhaust Pipe

There are several different configurations of exhaust pipe systems, 2 common examples are

The single system (1 tailpipe at the rear of the vehicle) or

The twin system, (2 tailpipes at the rear of the vehicle)

The piping itself has the role of connecting the various components and directing the gases away from the vehicle.

Due to the heat generated in an exhaust system sometimes the piping builds up condensation that sits in the pipes and may eventually rust through, causing the system to become noisy and allow gases to escape under the vehicle instead of being directed out the rear.

A damaged system will usually generate an increase in noise and should be inspected and serviced by qualified technicians.

Resonators and Mufflers

Both of these components are about reducing noise pollution to an acceptable level.

A resonator is a part of the system that encases part of the exhaust pipe designed to reduce certain noise frequencies in the system.

A muffler has exhaust gas flowing through it and internally it redirects the gas through a series of chambers designed to reduce the noise emitted at the tailpipe.

These are the basic components of an exhaust system.

With the requirement to decrease harmful emissions entering the atmosphere, required increases in fuel economy, there are various other exhaust components that play a vital role in the correct operation of your engine and its exhaust.

Modern exhaust systems are monitored, delivering information to the computer of your car, reacting to different climatic conditions and driving situations, so a correctly operating system is vital.

A fault in the system will alter the data sent to the computer and change the efficiency and performance of your vehicle.

A word about Diesel systems.

A diesel vehicle often produces a carbon build-up in the system that needs to be dealt with, so modern diesel systems often require more maintenance than its petrol counterpart when it comes to exhaust systems and their performance.

The worst condition for an exhaust system is a partial or even complete blockage of the system.

You then have an engine delivering extreme force to the exhaust manifold that is unable to escape into the atmosphere at an acceptable flow rate.

It’s a bit like blowing up a balloon, eventually, something has to give way.

Unfortunately, it is usually the engine of your vehicle, causing an expensive catastrophic failure that could have been avoided.

If you have a diesel vehicle ask your local Future Auto Service Centre on what is required of your system, they have a wealth of experience and knowledge in this area and are only too happy to assist.

Some other components you may hear of are

• DPF’s or Diesel Particulate filters
• EGR’S or Exhaust gas recirculation valves.
• Add Blue a fluid required by some diesel systems to reduce emissions.
• Oxygen sensors sample the levels in the exhaust system and deliver the information to the engine management system.

As emission regulations get tighter we are seeing more components developed and added into exhaust systems.

 Important information

• Exhaust systems run at extremely hot temperatures, never work on a hot exhaust.
• Exhaust systems produce dangerous gases, never work on an exhaust system in a confined space.
• Exhaust systems are set to work within legally set emission levels, it is illegal to tamper with these levels and adjustments.
• If a component in an exhaust system fails, it is often the end result of another issue that also needs to be addressed.
• Ignoring Exhaust system problems often leads to complete engine failure, requiring a replacement engine and the original exhaust repair.

At Future Auto Service Centres, when we are servicing your vehicle, we carry out an external inspection of your exhaust system and report to you any issues that require attention.

However, if your system suddenly becomes noisy or you are experiencing a lack of power from the engine, contact your local Future Auto Service Centre for an urgent inspection.

Our service centres are equipped with the tools, diagnostic equipment and fully trained staff to ensure your satisfaction and safety when it comes to your vehicles exhaust systems.