Your air conditioning (AC) system keeps you cool and dry when the summer heat is on, and when it’s working properly it makes it a real pleasure to be in your car, insulated from the weather outside. However, if you feel it’s not operating at its best, it may be that you need an air conditioning system service to bring it back up to scratch. Did you know that your air con system loses around 10% of its refrigerant each year? Also, that you should get your AC system serviced at 2-yearly intervals? Many motorists are unaware of the need to service the air conditioning system, as it often doesn’t appear on the manufacturer’s service schedule. If you’re feeling the heat, and you’re unhappy about it, you need to get an expert to take a look at your car’s system.
The AutoMend network has access to over 9,000 members situated all across the UK, and when you are looking for car or van maintenance services, they are the people to trust. Our members have made a firm commitment to delivering high quality services at value for money prices, so contact your nearest network member today to get your air conditioner checked out.
Air conditioning itself was invented in the 1900s so it’s not new technology. It began to be incorporated in luxury car models in the 1950s and is pretty much standard in all cars nowadays. Basically, the AC system still works the same way today as it did in the beginning, except the components have got a bit smaller and more efficient, and the controls have become a little smarter. The aim of your car air conditioning is to cool the air inside the car and remove some of the humidity. It does this by using three main components; a compressor, a condenser and an evaporator, plus refrigerant liquid and a few other essential processes which control the liquid and gas flows.
This is a pump, and it is driven by the car’s crankshaft via a belt. The AC system’s refrigerant is pulled into the compressor as a gas at low pressure. The compressor squeezes the gas and compresses it, which generates heat. The heated compressed gas is forced out into the condenser at high pressure.
This is a radiator, and its job is to take the heat out of the air con system. The highly pressurised refrigerant gas comes into the condenser from the compressor and flows through the condenser coils, which are air-cooled. The refrigerant gas cools, and this turns it back into a liquid, but it remains at high pressure.
The high-pressure refrigerant liquid is likely to contain water, which must be removed before it meets the evaporator. This is achieved by an in-line component called the receiver-drier which is a chamber filled with desiccant crystals (the kind you get in the little packets which are designed to keep electronic goods dry in transit). These crystals trap and retain any moisture from the refrigerant.
This is a special kind of liquid that has a very low boiling point, which means that it turns into a gas very easily. A toxic chemical called Freon used to be used, but this is an ozone-depleting agent if allowed to escape into the atmosphere. Freon has been replaced in modern systems by more environmentally-friendly alternatives. The replacement chemicals may be better for the environment but they are still toxic. The refrigerant liquid needs to be removed and contained using special handling techniques, which is why you should only let trained and authorised mechanics service your air conditioning.
The high-pressure refrigerant liquid is nearly ready to go into the evaporator, but first it passes through a system which allows the liquid pressure to reduce. In some vehicles, the pressure is reduced by a thermal expansion valve, in others by an orifice tube. Both systems regulate and control the flow of refrigerant to the evaporator, and these components are subject to wear or blockages, so need to undergo regular servicing at the same time as your air con service is carried out.
This is the step which actually cools the air inside the car. Unlike all the other components which are behind the bulkhead in the engine compartment, this component is usually in the passenger footwell. Operating like a radiator in reverse, the evaporator in effect absorbs the heat from the passenger cabin air.
The refrigerant is a liquid at low pressure and enters the evaporator at 0℃ which is the freezing point of water and explains why all the moisture needed to be removed at an earlier stage by the receiver-drier. The refrigerant liquid won’t freeze at this low temperature. It has such a low boiling point however, that the heat inside the cabin is enough to turn it from liquid to gas, and the gas can absorb a huge amount of heat. The gas carrying the heat (and some humidity) with it leaves the evaporator, and goes back to the compressor, ready to start the whole process over again. In the meantime, a fan blows air over the cold evaporator coil, and into the cabin, bringing cooling relief to driver and passengers.
Dealing with condensation is one of the highest priorities, and the advice is to run your air conditioning system regularly even in the winter to prevent a build-up of water in the system. If this is not enough to clear the system through, you may start to experience a musty or stale smell inside the car. This a sign of bacteria beginning to build up in the pockets of moisture in the air conditioner. If you begin to experience this, it’s vital to get the system checked out by an expert, as the bacteria can cause breathing problems and irritation for the eyes. Give your local AutoMend mechanic a call and get a professional opinion right away.
The other thing you can do is to get a professional air conditioning service carried out at least every two years. Service content varies, so always check what is included. You will need a top-up of the refrigerant to maintain the correct levels (a re-gas), or total refrigerant replacement if it has become contaminated. In addition, air and pollen filters need to be checked regularly. Oil or lubricant levels for the compressor, and a check on the efficiency of the receiver-drier valve and the thermal expansion valve or orifice tube may also form part of the service. Before you opt for the cheapest available option, check whether the cost of refrigerant is included or extra – it is costly to buy and requires careful handling so some garages charge extra. Your best option is to go to a trusted local garage – a member of the AutoMend network of car and van maintenance specialists is the logical choice.
We have network members spread far and wide across the UK, so you are never too far from professional maintenance and repair services. It’s easy to find your nearest garage or mobile mechanic – simply input your postcode and select your location. Then choose your vehicle type and the service you need, and we’ll show you all the local mechanics and their distance from you. Pick one or more and ask for a quote (free, no-obligation) or pick up the phone and give them a call – you’re on your way to getting your car air conditioning serviced without the hassle of having to search the internet and check multiple websites.