If you’re anything like us, the recent heatwave made one component in our VWs feel more important than almost anything else. Yes, it’s the air conditioning. Just imagine sitting in that stuffy, sweaty, overbearing heat without air con.
You’ll likely have encountered VW air con re-gassing before. In a nutshell, this means recovering the old refrigerant, checking the system, and refilling it with the correct amount of refrigerant and oil. As a general rule, you should have your air con checked and re-gassed roughly every two years.
If your VW’s air con no longer feels particularly cold, takes a long time to cool your cabin down, or hasn’t been serviced for a few years, it’s worth booking your air con service now.
In the meantime, this article explains how often you should get your VW’s air con re-gassed, and why.
What does your VW’s air con actually do?
Air conditioning is a form of heat exchange. It doesn’t simply ‘blow cold air’. Technically speaking, it removes the heat from hot air.
Your air con uses a refrigerant, colloquially referred to as ‘air con gas’ (hence, ‘re-gassing’). A compressor pumps this refrigerant around your VW’s AC system. As it moves through, components and pipe widths change its pressure, changing it between a gas and a liquid as it absorbs heat from inside the car and releases it outside.
This heat exchange has a happy and fortunate side effect. It removes humidity.
Taking the moisture out of the incoming air makes it feel even colder and makes your car even more comfortable. It also helps keep your windows from fogging up.
What is air con gas?
As we mentioned above, air con gas is a casual term for the air conditioning refrigerant. It circulates through the compressor, condenser, expansion valve and evaporator.
Older VWs often use R134a refrigerant, while most newer models use R1234yf. Since 2017, new cars and light vans in the UK have had to use lower global warming potential (GWP – see below) air con refrigerant, which is why R1234yf became the common replacement for R134a.
The exact type depends on the age and specification of your VW, which you can find in your owner’s manual. These gases aren’t interchangeable, so the system needs to be serviced with the correct refrigerant.
The refrigerant also works alongside oil in the system. This oil is mixed in with the refrigerant and helps lubricate components and protect seals.
GWP, measures how much heat a greenhouse gas traps in the atmosphere compared with carbon dioxide. The higher the GWP, the greater the potential environmental impact if that gas escapes.
How does car air con work?
First, the compressor pressurises the refrigerant. This raises its temperature and pushes it through the system. The hot, pressurised refrigerant then travels to the condenser, usually positioned near the front of the car. As air passes over the condenser, heat is transferred from the refrigerant to the outside air and blown away.
The refrigerant then passes through an expansion valve or similar control point, where its pressure drops. This makes it very cold. It then moves through the evaporator, which sits inside your VW’s heater and ventilation system. As air is blown across the cold evaporator and into the cabin, the evaporator absorbs its heat, giving you the cool air you feel through the vents. It then returns to the compressor, ready to start the cycle again.
If the refrigerant level is low, your AC can’t absorb and release heat as effectively. That’s when you may notice weaker cooling, longer cool-down times, or air that never gets cold. Other AC problems could also be responsible. For example, a failing compressor, compressor pulley, or an underlying refrigerant leak. A VW AC service is the best way to identify and repair these issues.
What does a VW air con re-gas do?
In theory, your air con system is sealed. However, because of pressure changes, vibration, age and general wear and tear, a small amount of refrigerant can escape over time through seals, joints, hoses and components.
An air con re-gas restores the correct amount of refrigerant to the system. It’s important to get your VW’s air con re-gassed by a qualified service centre. Technicians who recover F-gas from vehicle air conditioning systems need the correct F-gas qualification, so this isn’t a DIY top-up job.
During an air con service, a technician uses a specialist machine to recover your VW’s old refrigerant. This machine then conducts a vacuum test to check for any leaks. If all is well, it then adds the correct quantity of fresh refrigerant for your specific vehicle.
If your car’s AC was low on refrigerant, this can make a massive difference. You may notice colder air from the vents, faster cooling, better demisting and less strain on the system.
However, if the air con fails its vacuum test or is otherwise damaged, a re-gas isn’t a magic fix. If there’s a failed compressor, a damaged condenser, an electrical fault, a blocked component or a significant leak, a re-gas alone won’t fix the underlying problem. In most cases, the re-gassing machine will automatically halt the procedure if it detects a pressure problem. That’s why it’s sensible to have the entire AC serviced rather than just repeatedly trying to top it up. It can then be isolated and repaired before re-gassing.
How can you make your VW’s air con last longer?
Using your air con regularly is the best way to make your VW’s air con last as long as possible. So, run your air con for a short period throughout the year, even in winter. Keep the temperature turned up, so the cabin still feels warm, but the air con will help dry the air, reduce misting and keep the system’s seals and components working properly.
Running the AC as often as possible circulates the refrigerant and, most importantly, the oil. With the oil flowing through the system, the seals stay lubricated. This reduces the chance of them becoming brittle and developing leaks.
Another good tip is to keep your cabin filter in good condition. A severely blocked or dirty pollen filter restricts airflow, making your air con feel weaker even if the refrigerant level is fine. If your VW has poor airflow, unpleasant smells or misty windows, the filter may need checking.
Other than that, watch out for early warning signs such as warm air, unusual AC noises, bad smells, or the air con cutting in and out. Catching these small problems early usually helps prevent expensive repairs later.
Finally, book an air con service as part of your routine maintenance. Air con isn’t always included in a standard service or MOT, so it can easily be forgotten until it stops working on the hottest day of the year.
Book your VW air con service before summer
If your VW’s air con hasn’t been re-gassed for at least two years, or it no longer feels as cold as it should, we suggest having it checked. Here at Sunset VW in Derby, our VW air con re-gassing service restores your car’s cooling performance, protects the system and makes your car more comfortable in every season.
Book your VW air con re-gas today and enjoy cooler, clearer, more comfortable journeys.