Aircon blowing warm in
Slough?
Warm air does not always mean low refrigerant. We pump down, vacuum test and diagnose properly at our Slough workshop before quoting a single penny of parts. 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
- ✓Honest diagnosis before parts, every time
Aircon Not Cold? Pump Down and Vacuum Test in Slough
Aircon blowing warm air is one of the most common faults we see at our Slough workshop. Most drivers assume it just needs a re-gas. Often it does, but plenty of times the gas level is fine and the problem is a failed pressure switch, a sticking expansion valve, a knackered compressor clutch or even a blown 7.5 amp fuse. We diagnose properly before quoting parts.
Our pump-down and vacuum test gives us a real picture of what is actually wrong before anyone pays for anything. Berkshire drivers send us cars every week that have already had two or three re-gases elsewhere with no improvement. The answer was never gas.
Why your aircon might not be cold
- System is low on refrigerant. the simplest cause. A re-gas after a leak test fixes it. We confirm before charging
- Compressor clutch not engaging. you can hear it. Often a a fair amount pressure switch, sometimes a a fair amount compressor. Diagnose first
- High-pressure cut-out tripping. usually a blocked condenser face full of dead bugs and Berkshire road grime. Clean the rad pack and retest
- Expansion valve or TXV stuck. common on older Vauxhall, Ford and Mini. Symptom is iced-up pipework or no cold at all
- Cabin pollen filter completely blocked. air cannot move past the evaporator. Cheap easy win we check first
- Blend door actuator stuck on hot. all the cold in the world will not help if the heater door is open. Diagnose with a scan tool
What the pump-down and vacuum test tells us
We connect our recovery station, weigh out and recover whatever refrigerant is in the system. Step one already tells us if the system was undercharged (low gas) or overcharged (previous bad re-gas) or completely empty (major leak). Then we pull a deep vacuum and watch it for at least 10 minutes.
If vacuum holds, the system is sealed and we charge to factory weight. If it does not hold, we move into leak detection (UV dye and sniffer). Either way you get an honest answer that day, not 'we did a re-gas, see you next year'.
What the scan tool tells us about the rest
If pump-down and vacuum show the system is healthy, the fault is electrical or mechanical, not refrigerant. We plug in our diagnostic scan tool and read live data: refrigerant pressure sensors, compressor clutch command, blend door position, evaporator temperature. Most modern cars (BMW, VAG, Ford, Vauxhall, Tesla) will tell us exactly which component is misbehaving.
From there we quote you the actual fix. No 'might be this, might be that, leave the car with us for a week and we will keep trying'. One diagnostic, one quote, fixed price, your call on whether to proceed.
Where we are and who we cover
Aircon diagnosis for cars across Slough, Langley, Colnbrook, Datchet, Windsor, Maidenhead, Uxbridge and Gerrards Cross. Berkshire's straight-talking aircon workshop, five minutes from M4 J5 at SL3 7EW.
Aircon blowing warm? Call 01753 439115 or WhatsApp the Onyx Autocentre team on 07393 580281 with your reg and we will book you in for an honest diagnosis at our Slough workshop. 01753 439115 or WhatsApp 07393 580281.
More on car air conditioning: R134a Aircon Re-gas in Slough. Older Cars Welcome · R1234yf Aircon Re-gas. Slough and Berkshire · Aircon Leak? UV Dye Test Finds It Fast in Slough · Aircon Smell or Blocked Pollen Filter? Cleaned in Slough · Back to Car Air Conditioning
Aircon Not Cold? Pump Down and Vacuum Test in Slough 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, Stainesor Hayes, we'll book your aircon not cold? pump down and vacuum test in slough around your schedule. Same Slough workshop, same trusted team, same standard on every aircon not cold? pump down and vacuum test in slough 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
"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."
"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."
"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."
"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."
"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."
"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."
"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 aircon not cold? pump down and vacuum test in slough today. Slough, Langley, Colnbrook, Windsor, Maidenhead, Uxbridge and Gerrards Cross.