You should always take exhaust faults seriously. They are quite rare in modern cars, but they can be expensive and dangerous when they do arise. That's why you need to understand the importance of an exhaust repair or replacement. By the end of this article, you will understand:

  • The role your exhaust plays
  • How to identify an exhaust fault
  • How much an exhaust replacement and exhaust repair costs
  • The lifespan of your exhaust
  • Why an efficient exhaust is so important


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What Does an Exhaust Do?

The main function of the exhaust is to limit your vehicle's CO2 (Carbon Dioxide) and NOx (Nitrous Oxide) output. These are two harmful exhaust gases produced during combustion and are big contributors to Climate Change.

When fuel combusts, the chemical compounds produce waste gases as well as powering your vehicle. The exhaust manifold captures these gases so that they don't leak into the atmosphere straight away. Instead, it forces them back into the exhaust pipes. In petrol cars, these funnel the gases into the Catalytic Converter, or the Diesel Particulate Filter in diesel vehicles.

Whichever part your car uses, it converts the harmful gases into less toxic forms. These include Nitrogen and water vapour, which are much healthier for the environment. Your exhaust then pushes these fumes out and away from the rear of your vehicle. In diesel cars, the fumes are stored as soot which are burned off by a process known as 'regeneration'.

The exhaust system's secondary job is to make your car quieter. This is done by fitting a muffler. Without this part, cars wouldn't meet noise pollution limits in residential areas. Because no one wants to listen to a shouty exhaust all hours of the day do they?

The exhaust has several other jobs, including:

  • Keeping your engine running properly
  • Keeping your fuel economy as high as possible
  • Making sure waste gases don't flood the cabin. These could make you very ill otherwise.


close up of dual car exhaust with faint exhaust gases

Without an exhaust, your car would pump toxic gases straight into the atmosphere and your cabin - potentially poisoning you and your family!


Of course, exhaust components deteriorate with age. The toxic gases can cause corrosion, and rust and poor road conditions can cause external damage.

So, what should you look out for to diagnose an exhaust fault?


What Does Exhaust Rattle Mean?

Exhaust rattle usually means that the exhaust system is loose or misaligned. There are many reasons for this, including:

  • Rusted or missing brackets
  • External damage from a collision
  • Another loose part touching your exhaust system
  • As a result of a leaking exhaust.

If you hear an exhaust rattle, you should treat it as a serious fault. This does not mean you can just turn up your music to drown it out and hope for the best. A loose exhaust is an inefficient exhaust - and that could mean that Carbon Monoxide is filtering into your cabin. This silent killer is incredibly deadly and should be dealt with immediately.

If you hear an exhaust rattle, open the windows to keep your car well-ventilated and try to avoid sitting in your vehicle while it idles. If you start to feel dizzy or light-headed, stop driving immediately and get out of the car. This is a sure-fire sign that you are about to be overcome by Carbon Monoxide.


What Does Exhaust Noise Mean?

Exhaust noise can indicate a range of problems. If you hear a loud roaring noise while driving, it usually means that condensed exhaust gases have corroded your silencer. A hissing noise indicates a crack in the main exhaust manifold, exhaust pipe or a leaking head gasket. A chugging noise means that there is a blockage somewhere in your exhaust system and the gases aren't being expelled correctly.



Other Signs You Need an Exhaust Replacement

  • Patches of rust or corrosion that aren't just on the surface
  • Cracks or holes in any section of the exhaust
  • Weak structural integrity of the exhaust
  • Engine misfires. A leaking exhaust means more oxygen enters the engine. Your car's onboard computer registers this as inefficient combustion and injects more fuel into your engine. This makes the fuel too rich which can overwhelm your Catalytic Converter and cause it to fail.
  • Blue smoke from the exhaust. This happens when oil from the engine enters the fuel system. If blue smoke is accompanied by a burning smell, book an exhaust repair immediately. Grey smoke can also indicate an oil leak.
  • Black smoke. If you drive a petrol car, this can mean you need a new air filter as too much fuel is burning. In diesel cars, it's usually a problem with the Diesel Particulate Filter we mentioned earlier.


If you notice any of these warning signs, you shouldn't delay an exhaust repair. If you do, you can cause yourself plenty more problems.


Why is an Exhaust Replacement or Repair Important?

An inefficient exhaust will cost you a lot of money in the long run. It will reduce your fuel economy, can cause MOT failure and could see you pick up several fines.

If one part of your exhaust has a fault, it could put extra strain on other parts and increase your repair cost. Problems get worse the longer you leave them and this is bad news for your health, your car and your wallet.


car exhaust at rear of vehicle with thick heavy black smoke pouring into air

Any sort of heavy black smoke from your exhaust is a sure sign it needs an urgent repair!


How Much Does an Exhaust Replacement Cost?

A full exhaust replacement can cost anywhere between £500 and £2,000.

Fortunately, you might not have to replace the entire exhaust system. It's made up of 5 main parts:

  • Tail Pipe
  • Silencer
  • Catalytic Converter
  • Exhaust Manifold
  • Down Pipe

You can replace one or more of these parts individually. This directly impacts your exhaust replacement cost.

However, if you need a catalytic converter replacement, either on its own or with any other exhaust part, you could be staring down the barrel of a £1000+ bill!


Can You Repair an Exhaust Instead?

Yes, you can. If you want to keep your car running on a budget, you can patch up minor exhaust damage with a range of tapes, putties and other repair materials. You can buy these materials for around £20 each.

However, you should exercise caution when completing an exhaust repair yourself. Your car must still pass the required MOT emissions test, so your exhaust patch-job must solve your problem and keep your vehicle road legal. This can be a tough ask. We recommend booking a professional exhaust repair instead. A DIY job should only ever be a stop-gap measure before you can book your car into a local garage.


Can You Remove the Exhaust Completely?

No, you can't drive a car without an exhaust, even if you want to try and save money. It's very illegal and also very dangerous to do so. Exhaust fumes are more likely to leak into the cabin, potentially poisoning you and your family. Not only that but you could face three fines if caught:

  1. Driving a dangerous vehicle
  2. Driving a vehicle without a Catalytic Converter
  3. Driving an unroadworthy vehicle.

You will also break all sorts of noise and pollution laws as well.


Exhaust Repair Cost

The average exhaust repair cost is between £300 and £600. Smaller cars such as Kias and Dacias have the cheapest exhaust repair cost, family cars such as Ford, Peugeots and Vauxhalls are around £400 and an exhaust repair for a larger, more premium marque like a Land Rover is the most expensive.

When you book an exhaust repair at one of our UK garages, you can save up to 70% by comparing deals over booking directly. This gives you the best exhaust repair near you at the very best price. Enter your reg number and postcode to compare garages and see how much you could save today.



How Long Does an Exhaust Last?

Modern exhausts should last between 8-10 years, or 100,000 miles without developing problems.

Manufacturing methods have come a long way in recent years and exhausts are now made with corrosion-resistant stainless steel. These are able to handle the toxic gases better. This progress is thanks, in part, to stricter EU emissions laws.


How Long Does an Exhaust Repair Take?

The simplest exhaust repair can take as little as 30-60 minutes, but larger repairs can take upwards of 2 hours. As with anything, the more complex the exhaust repair, the longer it is going to take.

Once the mechanic knows what repair your car needs, they will be able to give an expected repair time to help you plan your day.



Your exhaust plays a vital role. It reduces your car's noise and pollution levels and keeps dangerous gases out of the cabin. However, any sort of rattle or noise can indicate a severe problem that needs to be fixed immediately.

An exhaust replacement can cost several thousand pounds, but you can also replace all the parts individually - which is good news for your wallet! Any experienced mechanic can diagnose the cause of your problem with a detailed inspection and may suggest an exhaust repair instead. This is a much cheaper option, but you should not try a DIY fix. An exhaust problem can lead to an MOT failure or fine for driving a dangerous vehicle.

If you have an exhaust fault, enter your reg number and postcode to compare and save on exhaust repair deals near you. Click here to compare instant prices on your exhaust replacement.