DPF, catalytic converter & exhaust repairs in Millbrook. Clean it before you replace it.
DVSA Approved MOT Test Station · Example demo station
A DPF light, limp mode, black or white smoke, an emissions fail on the MOT, or an exhaust that's started to blow. A blocked diesel particulate filter can very often be cleaned or regenerated rather than replaced, and an exhaust is replaced by the section, not the system. We diagnose first, then quote.
Diesel particulate filters (DPF)
The DPF traps soot and burns it off when the exhaust gets hot enough — which needs a decent run at speed. Short trips, town driving and the wrong oil stop that happening, the filter fills, and you get the DPF light, then limp mode, then a car that won't go above 40mph.
Clean or replace? If the filter is blocked with soot, a forced regeneration or a professional clean usually restores it, at a fraction of the cost of a new one. If it's cracked, melted or full of ash from years of use, it needs replacing. We check the differential pressure and the fault history first, so you get the honest answer rather than the expensive one.
A DPF that has been removed or gutted is an automatic MOT fail and illegal on the road. We don't do it.
Catalytic converters
An emissions fail on a petrol car, a rotten-egg smell, a rattle from underneath or a "catalyst efficiency" code. Before condemning the cat we check what's upstream: a misfire, a lambda sensor or an air leak will fail an emissions test with a perfectly good converter, and a new cat won't fix them. Where the cat is genuinely finished, we fit a quality replacement approved for your car.
Exhausts
- Blowing — a louder note, a blow under acceleration, fumes in the cabin. Usually a joint, a flexi pipe or a corroded section.
- Rattling — a broken hanger, a loose heat shield or baffles gone inside a silencer.
- Hanging low or knocking — perished rubber mounts.
We replace the section that's gone, refit hangers and clamps properly, and check the rest so you're not back in a month. Exhaust leaks and excessive noise are MOT fails.
What we do and what it costs
- Diagnostic scan and a look underneath: fault codes, DPF pressure readings, exhaust condition.
- Plain-English findings and a photographed quote with the options — clean, regenerate, repair a section, or replace — and our recommendation.
- The work, then a road test and a check that the warning light stays off.
Price: diagnostics at £48 per hour inc VAT; DPF cleaning, catalytic converters and exhaust sections quoted per car before any work starts. Diagnostics →
DPF, cats & exhausts questions
My DPF light is on. Can I keep driving?
If it's the first amber warning and the car drives normally, a 20-minute run at motorway speed in a middle gear often lets it regenerate. If the light stays on, the car is in limp mode, or the engine light has joined it, stop making short trips and book it in — driving on a blocked filter can damage the turbo and the engine.
Is DPF cleaning as good as a new filter?
For a filter blocked with soot, yes — a proper clean restores it and costs far less. A filter that is cracked, melted or full of ash cannot be cleaned and needs replacing. We check which before recommending either.
Why did my car fail the emissions test?
On a diesel, usually smoke from a tired DPF, injectors or EGR; on a petrol, a lambda sensor, a misfire, an air leak or a worn catalytic converter. The test result tells us which way to look, and we check the cheap causes before the expensive ones.
Do I need a whole new exhaust?
Rarely. Exhausts come in sections and we replace the one that has failed, with the hangers and clamps that go with it.
Can you remove my DPF?
No. It's an MOT fail and illegal on the road, and it usually makes the underlying fault worse.