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Why is my car are conditioning not working?

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There are many reasons your car's air conditioning (AC) does not work, we will discuss the most common reasons that we see why it may not be working. Most people do not bother with having their cars AC looked at when it has stopped working in fear of large repair costs. Over 70% of the time it is due to low refrigerant (gas) and a simple service gets it working again.

Most repairs are relativley cheap if they are diagnosed correctly.

We only charge £35 to diagnose the problem if your AC does not work due to a problem. 

Refrigerant loss

Most cars lose between 10-15% of refrigerant a year, this accounts for 70% of cars we see. this is the most common reason the cars AC has stopped working. It is recommended to have the AC services every 2 years to check the gas levels.

There may also be a leak in a pipe or condenser (Big Radiator behind the cars grill). Most small leaks can be repaired using Extreme Leak Additive. If it is a big leak, our mechanic can repair this using a special Two-Pack Putty designed for AC systems or fit a new condenser or pipe. Condensers usually cost around £250 supplied and fitted. 

Pressure Switch Fault


This is a common problem, the pressure switch monitors the pressure in the system and gets stuck in the off position. We can get most pressure switches working again, with the use of high pressure Nitrogen. If it needs a new one they are only around £20.

AC Solenoid valve as stopped working.

This allows refrigerant into the compressor and is common for them to stop working. This is only a £20 part and easily changed. Most common on VW, Audi, Skoda but also quite a few other car manufacturers now use them.

Thermal Expansion Valve Fault


Thermal Expansion Valve (TXV) is letting too much gas into the evaporator or is blocked. This is only a £25 part and eaily changed.  

Air trapped in system, this can cause the TXV to freeze and block the spray nozzle on the TXV. This is caused by not being Vacuumed on a previous service. This is easily fixed with a vacuum.

Too Much or too Little Gas in System

We see this regularly especially when a car as recently been serviced else where and the garage has put too much gas or too little gas. This is caused by scales on the machine not being calibrated.

​Compressor failure


We only see a few compressors a year fail, so it is rare for them to fail. Usually there is no compression or the compressor is making some strange sounds. Compressors are around £150-£250 new or £30 secondhand.

Fuse or Relay Problem

A simple blown fuse or a stuck relay can be the cause of the AC not working.

Some of the Diagnostic Equipment we have to find a fault

High Pressure Oxygen Free Nitrogen to pressure test system to locate leaks.

Ultrasonic Leak Detector.

Spray Bubble leak locating fluid.

Ultraviolet Lamp. to spot leaks.

Sight Glass to see any contamination in refridgerant.

Vacuum test.

Latest Computer Diagnostics.

R134a Leak Sniffer.

Diagnose High and Low Pressure readings to find out if AC is working correctly.

Vast experience gained over the years.

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