Boost leak & smoke test in
Slough.
Limp mode, whistle on boost, underboost codes, MOT emissions failure or a stubborn EVAP light? Our Slough workshop pinpoints the leak with a proper smoke tester, not guesswork. Berkshire and Heathrow drivers welcome. No nonsense. No hidden prices. Book in today.
⭐⭐⭐⭐⭐ 4.9 out of 5 from 500+ Google reviews. Trusted by drivers across Slough since 2019
- ✓6 months interest-free, up to £3,000
- ✓Same-day slots available in Slough
- ✓Smoke-tested with main dealer kit
What a smoke test actually tells you
Modern turbo engines run a sealed pressurised intake. A pinhole leak the size of a pencil lead is enough to drop boost, trigger limp mode, or fail an MOT on emissions. A smoke test seals the system, pushes low-pressure inert vapour through it, and the leak gives itself away. There's no guesswork, no parts gamble, no fitting four hoses to find one that was split. It's the right way to diagnose.
Cars we smoke test most often in Slough
- BMW N54 and N55 (135i, 335i, 535i, X3 35i, X5 35i, X6 35i). Plastic charge pipes crack at the throttle body union. Almost every one we see needs a forged or HPS replacement.
- VW / Audi 2.0 TFSI (Golf GTI MK6 & MK7, Audi S3 8P / 8V, Leon Cupra, Octavia vRS). PCV diaphragm goes, throws a P2279 or rough idle. Smoke test confirms it in seconds.
- Ford 1.0 and 1.5 EcoBoost (Fiesta ST, Focus ST, Puma, Kuga). Intercooler hoses split. Misfires, EML, no power.
- Diesel BMW N47 / N57 and VAG 2.0 TDI. EGR cooler leaks and intake manifold flap motor cracks. P0299 underboost on the scan.
- EVAP leaks (any petrol). Loose fuel cap, perished filler neck, cracked purge valve. Catch-all P0440 / P0455 codes.
What you get from us
A clear photo or short video of the leak, a written quote for the repair, and a straight answer on whether it's a quick fix or a bigger job. The team at Onyx Autocentre would rather lose ten minutes telling you it's a cheap vacuum hose than make up a turbo story.
We test cars from Slough, Langley, Colnbrook, Datchet, Windsor, Maidenhead, Uxbridge, Gerrards Cross and the wider Berkshire area every week. Five minutes from M4 J5, six from M25 J14.
Got a boost or EVAP problem? Call 01753 439115 or WhatsApp the team at Onyx Autocentre on 07393 580281 and we'll get you booked in today.
Need a deeper diagnostic on a fault code? See engine diagnostics.
Boost Leak & Smoke Test in Slough and across Berkshire
Onyx Autocentre is based in Slough, Berkshire and we look after cars from across the SL postcodes every day. Whether you're driving in from central Slough, West Draytonor Burnham, we'll book your boost leak & smoke test around your schedule. Same Slough workshop, same trusted team, same standard on every boost leak & smoke test job.
All our services
Every service we offer at our Slough workshop. Tap a tile to find out more.
- Air Bag RepairsFind out more
- Alloy Wheel Crack WeldingFind out more
- Alloy Wheel RefurbishmentFind out more
- Alloy Wheel WeldingFind out more
- Auto ElectricsFind out more
- Body Kit FittingFind out more
- Boost Leak & Smoke TestFind out more
- CambeltsFind out more
- Car Air ConditioningFind out more
- Car BatteriesFind out more
- Car BrakesFind out more
- Car ExhaustsFind out more
- Car ModificationsFind out more
- Car RepairsFind out more
- Car Safety ChecksFind out more
- Car ServicingFind out more
- Car TyresFind out more
- Carbon CleaningFind out more
- Cheap Car TyresFind out more
- Clutch ReplacementFind out more
- Diesel Performance ECU TuningFind out more
- Diesel TuningFind out more
- Dyno TestingFind out more
- ECU RemappingFind out more
- Engine DiagnosticsFind out more
- Engine ManagementFind out more
- Engine RebuildsFind out more
- Engine TuningFind out more
- Fleet MaintenanceFind out more
- Gearbox ServicingFind out more
- Gearbox TCU RemappingFind out more
- Haldex ServicingFind out more
- Head Gasket RepairsFind out more
- In-Car EntertainmentFind out more
- Mechanical RepairsFind out more
- MOT Failure RepairFind out more
- Nitrogen Oxide (NOx) Sensor RepairsFind out more
- Number PlatesFind out more
- Oil & Filter ChangeFind out more
- Parking SensorsFind out more
- Powder Coating for Alloy WheelsFind out more
- SteeringFind out more
- SuspensionFind out more
- Timing Belt ReplacementFind out more
- Trade Alloy Wheel RepairFind out more
- Turbo Intake CleaningFind out more
- Van Repairs & ServicingFind out more
- Vehicle SecurityFind out more
- Wet Belt ReplacementFind out more
- Wheel BalancingFind out more
- Window TintingFind out more
What Our Customers Say
Rated 5 Stars on Google by drivers across Slough and Berkshire
"Highly recommend this garage. After contacting a few other garages who didn't want to take my car in for diagnostics, these guys were happy to help. They diagnosed and fixed an engine fuel leak issue professionally and efficiently. Great service and very reliable. I'll definitely use them again."
"Very nice experience at Onyx — they took me in immediately and completed the DRL module swap efficiently. I have no regrets and would highly recommend."
"I brought my car to Onyx after visiting many other mechanics who failed to sort out issues with my vehicle. The mechanics here clearly explained the issues with the vehicle and fixed them quickly. Amazing service and wonderful people, highly recommend."
"Max and Ben are extremely professional and did an excellent repair on my wife's car at a great price. Max spotted the problem within 6 hours, which 2 other garages could not detect."
"I took my car to Onyx and met Ben who was friendly and I got the problem diagnosed by Ben which I had a faulty water pump. I was quoted a reasonable price and got it replaced. I was satisfied and would recommend Onyx."
"Brought my Audi S3 in for a coolant leak — the part was on back order but they managed to source one in a couple of days. Massive thanks to Ben."
"Took my BMW here for an oil change and oil filter and the service was spot on. Really friendly team, got the car booked in quickly and the job was done properly with no hassle."
"These guys are always polite and welcoming. I've taken multiple vehicles here and the service received has been excellent."
"Had the front pads done here over the weekend. Second time in with Onyx and service has been top notch both times. On time, no hassle and cost effective. Highly recommend."
"Great service, sorted out my alloy refurb at a good price and quick turnaround. Top service, highly recommend."
"A great experience with Onyx who fitted a new clutch for my Fiat 500. Super quick, friendly and well priced. Would highly recommend."
"Very friendly, no hassle effective service. Definitely recommend and will use when I need to get my alloy wheels refurbished."
"My vehicle went in for a brakes job and Ben and the team at Onyx Autocentre did an amazing job. Highly recommended."
Spread the cost over 6 months, interest-free.
Big bill? Pay the first instalment when you book, then spread the rest across up to 5 more monthly instalments, interest-free. Available on jobs up to £3,000. No setup fees, no hidden interest. FCA-authorised through Payment Assist, soft credit check, decision in minutes.
- ✓ Up to 6 months interest-free
- ✓ Available on jobs up to £3,000
- ✓ First payment at booking, rest split monthly
- ✓ Soft credit check, decision in under 2 minutes
- ✓ No setup fees, no hidden interest
Same-day slots are limited this week.
Call or WhatsApp now and get boost leak smoke testing today. Slough, Langley, Colnbrook, Windsor, Maidenhead, Uxbridge and Gerrards Cross.