If you've noticed a change in how your car sounds, a smell in the cabin, or vibrations and rattles from under your car, there's a good chance that your exhaust system needs an overhaul.  

Not only can an old exhaust affect your car's performance and efficiency, but it can also have serious health implications. So, add a new exhaust to your to-do list. 

So, what is the average exhaust replacement cost  – and how can you be sure it needs replacing? Keep reading to learn about new exhaust costs and signs to look out for. 

How much is a new exhaust cost? 

An exhaust system consists of many different but equally important parts. The cost to replace it will vary depending on your vehicle, the condition of the parts, and how they join together. Then there are also the labour costs to consider.  

Modern vehicles tend to use flanges with bolts to connect sections. These can be troublesome if the parts have succumbed to excessive rust, sometimes resulting in the need to replace multiple parts at once.  

So, there’s no one price for all exhaust replacements. However, we’ve provided some averages below. 

The average cost of exhaust replacement in the UK 

While this will vary depending on your vehicle and the garage you choose, a replacement exhaust will cost between £300 and £600.  

The price depends on whether it is a smaller vehicle, like a hatchback or a larger luxury vehicle. This price also changes depending on the parts and the labour involved.  

Luckily, it’s rare that an entire exhaust system will require replacing at once. The sections after the catalytic converter are usually the most susceptible to rust and damage. 

Split the cost into monthly payments with Bumper. 

Exhaust replacement costs by manufacturer  

So, how much is a new exhaust for each car manufacturer? Take a glance at the table below for averages for each car make. 

Exhaust replacement costs by location  

Alongside your car make and age, a new exhaust cost depends on where in the UK you’re based. Urban areas tend to have higher costs than rural garages.  

Here’s a quick overview of how prices can change. 

What parts make up an exhaust system? 

It's rare to need to replace a whole exhaust system at once. Exhaust systems are made up of multiple components for ease of manufacture, installation, and repair.  

The cost of replacing each of these exhaust parts varies greatly depending on the type of car, the part in question, and the state of corrosion under the vehicle.  

In order, from the engine to the rear bumper, the parts below make up your car's exhaust. 

1. Exhaust manifold 

A manifold is a part that connects multiple routes for gases or liquids into one pipe. In this case, a car's exhaust manifold bolts to the side of the engine and routes the exhaust gases from each cylinder into one pipe. 

This pipe is often called the down-pipe simply because it almost always runs straight down the side of the engine to the car's underside.  

If your car is turbocharged, the turbo will be mounted to the manifold/downpipe component, making removal more complex. There is likely also to be a Lambda sensor here. This measures the oxygen levels in the exhaust gases—useful for the engine's computer. 

How much does it cost to repair an exhaust manifold leak? 

Because the manifold is bolted to the engine, quite a few components often need to be removed before it can be inspected or fixed. If the original one is leaking, a replacement manifold would be moderately expensive as it is a complex and infrequently replaced part. 

There is also a manifold gasket that seals between the manifold and engine block. These can break and need to be replaced. The part is cheap, but replacing it can take a few hours. 

Leaks at the bottom of the manifold between it and the flexi, cat or mid pipe (depending on the car) can be pretty reasonable to fix. 

• New Manifold Cost:  £300-£1,000 
• Manifold Gasket Cost:  £300-£400 
• Seal between manifold and rest of exhaust Cost:  £40-£150 

2. Catalytic Converter 

Many cars now have the catalytic converter built into the downpipe, or at least the front section of the exhaust, that runs under the engine. Some vehicles also feature a secondary cat, somewhere along the midsection. 

The catalytic converter contains materials such as Platinum and Palladium, which react with the exhaust gases to remove some harmful components.  

For this reason, catalytic converters are often the target of thieves. They can be worth hundreds of pounds in scrap. 

How much does it cost to repair a catalytic converter? 

The cost of a replacement OEM catalytic converter is between £600 and £1,000, while the cost of a type-approved catalytic converter replacement will be between £300 and £500. 

Because the catalytic converter, or 'cat', contains exotic elements used to reduce harmful emissions, it is expensive to manufacture and, therefore, replace. Unfortunately, this has led to a trend of them being stolen from particular vehicles.  

An OEM (Original Equipment Manufacturer) cat will be more expensive than a generic off-the-shelf device. The issue is that the latter will take some degree of fabrication to install instead of just bolting in.  

Aftermarket cats are also usually less effective at filtering emissions, although, as long as the new part is 'type approved', it should not usually affect the MOT emissions test.

3. Mid Section 

As the name suggests, this is the middle section of the exhaust. In many cars, it contains a silencer, resonator, and secondary Lambda sensor. 

The silencer simply baffles and reduces the sound of the escaping gases, and the latter removes high-pitched elements to the exhaust sound without affecting the sound.  

The secondary Lambda is primarily used to detect whether the catalytic converter is doing its job by monitoring the exhaust gases after they have passed through it. 

Some luxury cars will have two silencers in this section, along with a resonator and a sensor, making it a large and heavy item. 

How much does it cost to repair an exhaust mid-section? 

• Cost to replace Mid section: £300 - £500 
• Cost to replace Midsection (luxury car): £300 - £700 

If your car is a high-performance or luxury model, expect to pay slightly more, as the mid-pipe may contain extra silencer boxes, increasing the part cost. 

This is where the age and complexity of the car can make a large difference. If the exhaust is overly rusty and bolts cannot be undone, sections in front and behind the midsection may need to be replaced. 

4. Diesel Particulate Filter 

Found on all diesel vehicles from 2009 onwards, these are extra filters that collect the soot that diesel engines produce. They are slightly different from normal exhaust silencers or catalytic converters in that they gradually fill up with deposits from the fumes.  

The car's ECU runs regeneration cycles to heat up the exhaust enough to burn out the soot into ash. Depending on the car, this would generally happen every 200-500 miles. The DPF will clog if not driven for long periods. 

How much does it cost to repair a clogged DPF? 

You can expect to pay between £100 and £ 250 to clean and repair a DPF, and between £300-500 to replace a DPF. 

Fixing a clogged DPF can be very expensive, depending on what tools the garage has available. There are services that can clean a DPF of the built-up soot and allow it to be used again, though sometimes this is not possible.  

5. Back Box 

Underneath the rear bumper, the back box connects to the midsection and further reduces the sound level of the car's engine using baffling materials such as mineral wool. The back box also features the exit tip visible from the car's rear. 

Some vehicles, especially performance ones, will have a box running the entire car width, with two exhaust tips for extra flow.  

How much is a new exhaust back box? 

Replacing the exhaust back box will cost between £250-£600.  

This is another part that will vary depending on the type of car. On the one hand, it has fewer flanged connections to become rusty, but it is also at the rear of the car near the wheels, meaning it gets splashed with road water, salt and mud.  

6. Exhaust Hangers, Sensors and Flexible sections 

We've gone over the main exhaust sections, but there are other components that are essential for successful operation.  

The exhaust hangers attach the exhaust to the car. Because the engine vibrates significantly, the exhaust cannot be rigidly bolted to the vehicle. Instead, rubber hangers are used with steel brackets to suspend the exhaust system.  

As well as using rubber hangers to reduce vibration, flexible sections are often incorporated into exhausts, usually between the manifold/downpipe and mid-section. These are to allow any movement engine not to cause strain on the exhaust sections. 

As mentioned in the previous sections, there is likely to be one or more Lambda sensors on the exhaust system. These relay information about the engine's exhaust gases to the ECU via wires routed inside the car. 

How much does it cost to replace a Lambda sensor? 

The approximate replacement OEM Lambda sensor cost is from £100 to £250. 

Not only are the oxygen or ‘Lambda’ sensors complex, but they also have to survive harsh conditions under the car, being heated to over 300 degrees inside the exhaust. They can often fail through the vibrations and movement experienced by the cable that runs to the ECU. 

When replacing a sensor, it’s usually best to go for a genuine part from the manufacturer. Aftermarket ones tend to cause erroneous engine malfunction lights and will not last as long. 

How much does it cost to replace an exhaust flexi pipe? 

Replacing a new exhaust flexi pipe will cost between £120 and £1000, depending on the vehicle. 

This stainless-steel tube, situated between your Oxygen Sensor and Catalytic Converter, gives your exhaust line more flexibility when moving and helps reduce the effect of vibrations on other parts of your engine.  

If it becomes cracked or broken, you may notice a decrease in engine power, a loud exhaust, or even a dragging exhaust pipe.  

A simple leak fix may only mean repair and labour costs, but replacing a flexi pipe can become very costly. 

How do you know if your exhaust needs replacing? 

With so many parts of your exhaust to consider, there are a few different signs that signal your system has a fault.  

Some of the most common signs that you need to replace your exhaust include: 

• Reduced fuel efficiency – Exhaust leaks can increase engine temperature and reduce efficiency, meaning you use more fuel than usual. 
• Reduced engine performance – Issues with your catalytic converter may reduce your acceleration power when driving. 
• Noises, such as hissing, roaring or rattling parts - These may be caused by leaks or loose parts. 
• Vibrations – Vibrations tend to be caused by a rusty exhaust pipe. 
• Burning smell - Leaks in your exhaust system can release hot gases into the engine, which can melt plastic parts and cause an unpleasant burning smell. 
• Gas smell - Like a burning smell, a gas-like smell can be caused by leaks in your exhaust system. 
• Check Engine Light – If your check engine light turns on, you should get to a garage as soon as possible. 
• Rusting or sagging parts – You may notice rusting or sagging parts at the back of your vehicle. These can signal the need for a new exhaust. 

Is it illegal to drive with a broken exhaust? 

Yes. It's illegal to drive with a broken exhaust system in the UK. We suggest you get it fixed as soon as possible!  

Will a broken exhaust fail an MOT? 

Yes. If a significant leak or unsafe emissions are coming from your exhaust, your car will fail its MOT.  

If it's just minor corrosion, then you will likely receive only an advisory note. 

How important is it to fix your exhaust system? 

Most of us are guilty of putting off car servicing and repairs to some degree, but your car's exhaust system is not something you should ignore. 

At best, the exhaust fault will affect the engine's performance, often causing higher fuel consumption and less power output. Failing to repair some parts in a timely manner can result in much larger repair bills down the road.  

Negative effects of a broken exhaust system 

The main reason to repair your exhaust immediately is for your and your passengers’ health. Exhaust systems exit at the back of the car to keep the fumes away from occupants. Leaks from any exhaust joints or components can easily cause dangerous gases to enter the cabin. 

Furthermore, detecting when the fumes are entering might not be possible, as you may become accustomed to the smell over time.  

Breathing in exhaust fumes can lead to headaches, sickness, and fatigue. None of these are ideal whilst driving a vehicle. 

You should always ask for advice from a mechanic. If you’re unsure what to do, find local garages near you with our garage search. 

New exhaust costs - The bottom line 

Realising you need to replace your exhaust system isn’t fun. However, driving with faulty exhaust parts can be a serious health hazard. Hopefully, this blog has helped you troubleshoot your issue and estimate approximate costs. 

Think your exhausts may need replacing?  

Search for a local Bumper partner garage on our website and benefit from 0% interest and monthly payments on your exhaust repairs. Find out more about how 0% car repair loans work. 

Author - Joseph Law

Joseph has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.