Exhaust

MOTRIO garages carry out the full range of exhaust system services on all makes and models, including diesel, petrol and hybrid vehicles. The service includes exhaust repair (silencer, exhaust pipe, mountings, gaskets and clamps), catalytic converter inspection and replacement, DPF cleaning and replacement on diesel vehicles, lambda sensor check, full emissions diagnostic and a final road test. Exhaust repair prices are confirmed by upfront quote before every job. The service is available by appointment at MOTRIO garages across the UK, with manufacturer-equivalent quality parts and a 1-year warranty on parts and labour.

Book your exhaust repair, catalytic converter replacement or DPF cleaning directly at your nearest MOTRIO garage. The MOTRIO network covers the whole of the UK, ready to work on any vehicle at the right price, with a 1-year warranty on parts and labour.

Find your nearest MOTRIO garage

In addition to exhaust repair, MOTRIO garages offer a full range of services for your vehicle. From regular maintenance to the braking system, from tyres to the battery:

• MOT → pre-MOT inspection (exhaust is the #1 cause of MOT failure)

• AdBlue & additives → AdBlue top-up for diesel SCR systems

• Electronic diagnostics → lambda sensor, DPF and EGR fault codes

• Vehicle maintenance → full service and engine check-up

Unusual noises, exhaust smells inside the cabin, a loss of engine power, or excessive fuel consumption are indicators that should not be ignored. Other signs to watch out for:

• Loud, rumbling or roaring exhaust note — usually a hole in the silencer or a corroded pipe (a ‘blowing exhaust').

• Hissing or tapping sound from under the car — small leak in a joint, gasket or pipe.

• Vibration through the steering wheel, pedals or seat — a loose or damaged exhaust mounting.

• Black, blue or white smoke from the tailpipe — sign of a deeper engine or DPF issue.

• Increased fuel consumption with no change in driving style.

• Engine warning light, DPF warning light or emissions warning light on the dashboard.

Important: exhaust fumes inside the cabin are dangerous. Carbon monoxide is colourless and odourless and can cause drowsiness, headaches and — in severe cases — loss of consciousness. If you smell exhaust gases inside the car, drive with the windows open and book a MOTRIO exhaust diagnostic as soon as possible.

The catalytic converter (often called ‘cat') is a part of the exhaust system that turns harmful gases produced by the engine — carbon monoxide, hydrocarbons and nitrogen oxides — into less harmful ones: carbon dioxide, water vapour and nitrogen. It is mandatory on all petrol cars from 1993 and on diesel cars from 2001.

Common signs of a failing catalytic converter:

• Engine warning light on the dashboard.

• Failed MOT emissions test — one of the most common reasons for diesel and petrol MOT failures.

• Rattling noise from under the car (loose ceramic substrate inside the unit).

• Sulphur or ‘rotten egg' smell from the exhaust.

• Loss of power or hesitation under acceleration, especially uphill.

• Excessive fuel consumption.

Catalytic converters can also be stolen — a known issue in UK car parks, especially on hybrid models. If your car suddenly sounds like a race car and the engine warning light comes on, check underneath: a missing cat is unfortunately not uncommon. At a MOTRIO garage we can supply and fit a manufacturer-equivalent replacement, including the heat shields and brackets needed to deter future theft.

A diesel particulate filter (DPF) is a component fitted to all diesel cars sold since 2009 (and many earlier ones). It traps the fine soot particles produced by combustion and burns them off in a process called regeneration, which happens automatically when the engine reaches a high enough temperature for long enough.

How to keep your DPF healthy:

• Drive on the motorway or A-road for 30–40 minutes once a fortnight at over 40 mph — this lets the DPF reach the temperature needed for regeneration.

• Use the right oil grade: the wrong engine oil produces extra ash that the DPF can't burn off.

• Don't ignore the DPF warning light: the earlier you address it, the cheaper the fix. A blocked DPF can cost over £1,000 to replace.

• Avoid only short urban trips: the engine never gets hot enough for regeneration and soot builds up.

• Top up AdBlue regularly (on cars fitted with SCR, see also our AdBlue service in Vehicle maintenance).

If your DPF is already partially blocked, a MOTRIO garage can carry out professional DPF cleaning — usually a fraction of the cost of a replacement. A forced regeneration with diagnostic equipment, a deep chemical clean or a removed-DPF clean are all options depending on the level of contamination.

Yes, and it's one of the most common reasons cars fail their MOT. The exhaust is a specific MOT checkpoint and the test inspects three main aspects:

• Emissions: CO and HC for petrol, smoke opacity for diesel. Modern cars must also meet stricter limits if originally homologated under Euro 5/6.

• Mechanical condition: any visible leak, hole, broken mounting, missing heat shield in a critical area or major corrosion will fail.

• Noise: an exhaust significantly louder than the manufacturer's original specification can also fail.

Specific items that cause an MOT failure:

• Missing or removed catalytic converter or DPF.

• Leaks in the exhaust system.

• Excessive smoke from the tailpipe (especially blue or thick black).

• Insecure or hanging exhaust components.

A pre-MOT exhaust inspection at a MOTRIO garage takes around 30 minutes and shows exactly what needs fixing before the official test — far cheaper than a retest fee and the time off the road.