Published · 2 min read
Air-con service: why, how often and what happens
Why an air-con system loses performance even without a fault, how you notice it, and why it is fine to run it in winter too.
A car’s air conditioning is a closed circuit, yet never completely sealed: over the years a little refrigerant escapes through hoses and seals. That is normal. It becomes a problem when the charge drops too far.
Signs it is time
- The system cools more slowly or less than it used to.
- The vents smell musty, especially when you switch it on.
- In damp weather the windows stay misted up for longer.
- The compressor makes unusual noises.
Why too little refrigerant does damage
The oil that lubricates the compressor circulates with the refrigerant. Less refrigerant means less lubrication. And the compressor is the most expensive part of the system.
What happens during an air-con service
- Recover the refrigerant and measure the amount. That shows us how much was missing.
- Evacuate the system. The vacuum removes moisture and shows whether the system is sealed.
- Refill with the amount the manufacturer specifies, plus compressor oil.
- Function test: we measure the temperature at the vents.
We also look at the cabin filter. It keeps out pollen and dust and is changed as the manufacturer specifies, usually with the service.
How often?
Many manufacturers and motoring clubs recommend an air-con service every two years. The drier, which filters moisture out of the circuit, we replace as the manufacturer specifies and whenever the system is opened for a repair.
R134a or R1234yf?
Older cars run on R134a refrigerant, newer ones mostly on R1234yf. Since 2017, new cars sold in the EU have had to use a refrigerant with a low climate impact. The two must not be mixed. Our service unit handles both.
Tip: switch it on in winter too
Air conditioning dries the air and so helps against misted windows. Running it regularly also keeps the seals and compressor lubricated. In frost, many systems switch the compressor off automatically.