The catalytic converter is located underneath the car, fitted into the exhaust system between the engine and the silencer. On most petrol cars it sits close to the engine, just after the exhaust manifold, and many cars carry a second converter further back under the floor. If you follow the exhaust pipe back from the engine, the converter is usually the first wider metal canister you reach, often hidden behind a thin heat shield.
The catalytic converter is located in the exhaust system under the car, between the engine and the rear silencer. According to the RAC, catalytic converters are located under the car and attached to the exhaust pipe, and petrol and diesel vehicles all have one – only full electric vehicles do not.
The exact position depends on the engine and the layout of the car. Exhaust gases leave the engine through the exhaust manifold, pass through the converter, then carry on through one or more silencers to the tailpipe. Because a converter only works properly once it is hot, manufacturers tend to place it as close to the engine as the design allows.
| Vehicle type | Where the converter usually sits | What to know |
|---|---|---|
| Petrol car | Just after the exhaust manifold, sometimes with a second unit under the floor | The front unit can be hidden behind the engine or a heat shield |
| Diesel car | Close to the engine, usually followed by a DPF | Other emission parts in the same area can look similar |
| Petrol hybrid | Under the car, in the exhaust, as on a petrol car | A common theft target |
| SUV, 4×4 or van | Under the vehicle, with more ground clearance | Easier to see, and easier to reach |
| Fully electric car | None | No exhaust, so no catalytic converter |
Source: RAC; Metropolitan Police; GOV.UK MOT inspection manual.
On petrol models, the honest answer to where is the catalytic converter on a car located is “right behind the engine”. Many modern petrol engines use a close-coupled converter that sits directly after the exhaust manifold, and some combine the manifold and the converter in a single part. Larger engines and some older designs add a second, underfloor converter further back, before the silencer.
That close position helps the converter warm up quickly after a cold start, so it begins cleaning the exhaust sooner.
On a diesel, where is catalytic converter on car depends on how many emission parts the system carries. The GOV.UK MOT inspection manual lists diesel oxidation catalysts, diesel particulate filters and selective catalytic reduction among the emission control equipment found on diesel vehicles. The oxidation catalyst usually sits first, close to the engine, with the DPF straight after it or inside the same housing.
Hybrids use a petrol engine, so their catalytic converter sits in the exhaust under the car in the same way. The difference is how often it works. The RAC notes that hybrid converters see less action, so the metals inside are usually less corroded – one reason they attract thieves.
Where on a car is the catalytic converter on a 4×4 or a van? In the same place – under the vehicle, in the exhaust – but with far more space around it. That extra ground clearance makes it easier to spot, and also easier to reach with a cutting tool. The Metropolitan Police warns that vehicles that sit high above the road are particularly vulnerable to converter theft.
A catalytic converter in a car is a metal canister in the exhaust that uses a coated honeycomb to turn harmful exhaust gases into less harmful ones before they leave the tailpipe. If you want to know what is a catalytic converter in the simplest terms, it is the main emissions clean-up device on a petrol or diesel engine. People who search “what is catalytic converter in a car” usually also want to know why it matters, and that comes down to the chemistry.
Put simply, what catalytic converters do is speed up chemical reactions in the hot exhaust gas. Carbon monoxide and unburnt hydrocarbons are oxidised into carbon dioxide and water vapour, and on petrol engines nitrogen oxides are reduced to nitrogen.
So what’s the purpose of a catalytic converter? It keeps exhaust emissions within the limits the engine was approved to meet. Without one, the RAC says, a car will produce emissions above legal limits. For a closer look at the different designs, see Blancomet’s guide to the main types of converter, from two-way to three-way units.
| Exhaust gas | What the converter does | What comes out |
|---|---|---|
| Carbon monoxide (CO) | Oxidises it | Carbon dioxide (CO2) |
| Unburnt hydrocarbons (HC) | Oxidises them | Carbon dioxide and water vapour |
| Nitrogen oxides (NOx) | Reduces them (petrol three-way converters) | Nitrogen |
Source: The AA, catalytic converter theft guidance; Britannica, “Catalytic converter”.
What is catalytic converter in car exhausts made of? A stainless steel shell holds a ceramic or metallic honeycomb, and that honeycomb is coated with small amounts of platinum, palladium and rhodium, which drive the reactions. Those metals are why thieves target converters and why old units are worth recycling. Blancomet’s article on ceramic and metallic converter designs explains how the two substrates differ.
The clearest sign that your car’s catalytic converter has been stolen is a sudden, very loud exhaust note when you start the engine, because the exhaust now has a gap where the converter used to be. A failing converter gives quieter clues: an engine warning light, poorer performance, a smell of rotten eggs or a rattle from underneath the car.
The MOT treats this seriously. The GOV.UK MOT inspection manual names catalytic converters as emission control equipment, and lists manufacturer-fitted equipment that is “missing, obviously modified or obviously defective” as a major defect, which means the car fails.
Where is a catalytic converter on a car most exposed? Underneath the car, where a thief can reach it with one side jacked up. The Metropolitan Police says converters can be removed in less than a minute, and that hybrid vehicles are most commonly targeted because their metals are more valuable.
Where is a catalytic converter located on a car you own? Start at the engine and follow the exhaust back. You do not need to go underneath to find it: with the car on flat ground, the engine off and the exhaust fully cold, look under the front edge and along the sides of the car with a torch.
Never get under a car that is held up only by a jack. If you need a closer look, ask a garage to check it on a ramp. The RAC also suggests searching the make and model of your vehicle if you cannot find the converter yourself.
Where is catalytic converter located if all you can see is a thin, shiny metal cover? Usually directly behind it. Most converters sit under a heat shield that protects the floor and nearby parts from the heat they give off. You do not need to remove it to confirm the location.
If a catalytic converter for car use has been stolen or has failed, the car needs a replacement that suits that vehicle and still lets it meet its emission limits at the MOT. Garages and exhaust centres can fit either an original equipment part or an aftermarket replacement. Deciding where to get catalytic converter recycling done for the old unit is a separate step, covered below.
A React catalytic converter comes from a range of replacement converters sold through Euro Car Parts in the UK, which has included type-approved units. Aftermarket converters like these are made to replace the original part. When it comes to recycling, an aftermarket unit is assessed on its own metal content, which can differ from that of the original equipment it replaced.
An old car catalytic converter should go to a licensed scrap metal dealer or a specialist recycler, not into general scrap. The platinum, palladium and rhodium on its honeycomb can be recovered and reused. At Blancomet, each unit is valued by in-house inductively coupled plasma optical emission spectrometry (ICP-OES) analysis of its real metal content, and payment is made by bank transfer, never cash, in line with the Scrap Metal Dealers Act 2013. For the full picture, see Blancomet’s complete guide to recycling and selling in the UK.
From your car to recovery
What happens to your old catalytic converter
A converter keeps its value through six simple steps – and most of the value is protected before it ever reaches the lab.
A garage or dismantler removes the converter in one piece. Do not cut it open or empty the honeycomb.
Photograph any codes stamped on the shell and note the make, model and year of the vehicle.
Drop it at a branch, send it by insured courier, or book free UK-wide collection for 10 or more units. Bring photo ID.
The unit is de-canned, and its contents are ground into powder and homogenised, so a sample reflects the whole unit.
In-house ICP-OES (inductively coupled plasma optical emission spectrometry) analysis measures its real platinum, palladium and rhodium content.
Payment is made by bank transfer, never cash, in line with the Scrap Metal Dealers Act 2013. Spot purchases are paid the same day once the price is agreed.
Practical takeaway
A converter that arrives whole, identified and with paperwork is the easiest to value – the laboratory analysis does the rest.
Source: Blancomet catalytic converter recycling service, 2026.
Before you hand over an old unit, a short catalytic converter car checklist saves time and protects the offer:
So, where is the catalytic converter located on a car? Underneath it, in the exhaust between the engine and the silencer, usually close behind the engine and sometimes with a second unit under the floor. The same answer covers where is the catalytic converter located in a car of almost any type, with only fully electric cars going without one.
If you have an old, damaged or replaced converter, do not leave it in the garage. Bring it to a Blancomet branch in Stone, St Albans, Leeds, Dunfermline, Gateshead or Dublin, send it by insured courier, or book free UK-wide collection for 10 or more units through Blancomet’s recycling service.
Where is the catalytic converter located on a car?
The catalytic converter is located underneath the car, in the exhaust system between the engine and the silencer. On many petrol cars the first converter sits right after the exhaust manifold, with a second unit further back under the floor. Only fully electric cars have no converter.
Do all cars have a catalytic converter?
Petrol, diesel and hybrid cars all have at least one catalytic converter. Fully electric cars do not, because they have no engine exhaust to clean. Diesel cars often carry extra emission parts as well, such as a diesel particulate filter.
Will my car pass its MOT without a catalytic converter?
No, not if the car was built with one. The MOT inspection manual lists manufacturer-fitted emission control equipment that is missing, obviously modified or obviously defective as a major defect, which is a fail. The car will also be much louder and produce emissions above legal limits.
How do I know if my catalytic converter has been stolen?
The most obvious sign is a sudden, very loud roar from the exhaust when you start the engine. You may also see a cut section of pipe underneath the car or an engine warning light. If you suspect theft, report it to the police and avoid driving the car further than necessary.
Why do thieves target catalytic converters?
Catalytic converters contain platinum, palladium and rhodium, which are valuable precious metals. They sit underneath the car and can be cut out quickly, and hybrids and vehicles that sit high above the road are particularly vulnerable.
Is a diesel particulate filter the same as a catalytic converter?
No. A diesel particulate filter (DPF) traps soot from diesel exhaust, while the diesel oxidation catalyst does the catalytic work, although the two often sit next to each other or in the same housing. Specialist recyclers such as Blancomet buy both.
What should I do with an old catalytic converter?
Sell it to a licensed scrap metal dealer or specialist recycler rather than putting it in general scrap. Keep it in one piece, photograph any codes and bring photo ID. Blancomet values each unit by laboratory analysis and pays by bank transfer, with free UK-wide collection for 10 or more units.
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