June 01, 2021

“How much for a re-gas?” In our vehicle air-conditioning business this is the most common enquiry we receive from our customers. It’s frustrating when you lose the cooling from your air-conditioning, or indeed if the windscreen demister isn’t working in the winter time. But is a re-gas the correct course of action when your car’s air-conditioning has stopped working?

First it’s important to note that there are many different aspects to the workings of an air-conditioning system, and a loss of refrigerant is only one possible reason for a loss of performance. It’s quite possible that the problem may lie elsewhere, so when we appraise a car’s air-conditioning system we will always check the controls and associated electrical components to see if the system is being turned on and off correctly. For certain models of vehicle there are common electrical faults that arise with the air conditioning and Morrison's technicians have the experience to find and diagnose these expediently.

When we do suspect a loss of refrigerant from the system we will recover the remaining refrigerant and weigh it to determine exactly how much has been lost. (While checking the pressures in the AC system with gauges gives an indication of whether refrigerant is in the system, it does not tell you the quantity that is present.) Refrigerant is not used up in air-conditioning systems, rather it is constantly cycled around the system and re-used. Given the terrible global warming properties of refrigerant, air-conditioning systems in cars are fully sealed with the intention that the refrigerant does not escape. While older cars did lose in the region of 10% of their refrigerant every year, improvements in design have now been made and in modern vehicles the rate of loss should be minimal.  So when we encounter a vehicle that has lost its refrigerant this nearly always indicates the presence of an abnormal leak that needs to be found and remedied.

Leaks can occur anywhere in a car’s AC system. There are many possibilities - sometimes it’s just an O ring that needs to be replaced, or there may be a leaking hose or a failed component. There is oil in a car’s air-conditioning as well as refrigerant, and when the refrigerant leaks out the oil does too. Often we are able to find telltale signs of oil staining or dirt stuck to oil where the leak has occurred. However, if there are no visual signs we may need to use trace gas and a sniffer to locate the leak. Another approach is to add an ultra violet dye to the air conditioning system and run it for a period of time to help us find the leak.

“Can’t you just re-gas it for now?” is another question that we are asked. If the air conditioning system is not properly sealed our answer to this is no for a number of important reasons. Naturally if the system is leaking then any new refrigerant that we put into that  system will go the same way as the old - that is, out of the car and into the atmosphere. We hear of far too many instances where a vehicle has been taken somewhere for a re-gas, only for the system to lose its refrigerant again within a very short space of time. In such cases the customer’s money has been wasted, and sadly another full charge of highly global warming refrigerant has been allowed to escape. Yet perhaps an even-worse scenario is when a vehicle has a slow leak and is then repeatedly regassed, perhaps every year or so. The air conditioning system does not cope well with being run low on gas as this causes the compressor (the pump in the system) to get hotter and work harder than is normal. Remember that a leaking system is losing its oil as well as its refrigerant, and the lack of oil will also cause premature wear of the compressor. These conditions will significantly shorten the life of the compressor and sooner or later it will fail, leaving the customer with a much more expensive air conditioning repair to address than fixing the original leak would have been.

It may shock customers to learn that the global warming potential of R134A (the refrigerant in use in the vast majority of vehicles in New Zealand) is some 1300 times higher than carbon dioxide. In light of the harm such refrigerants cause to the environment there is legislation in New Zealand (the Climate Protection Act 2002) prohibiting the re-gassing of leaking air conditioning systems. Unfortunately in spite of these facts there is still widespread malpractice around re-gassing vehicles by those who would ignore the law in the interest of making a quick buck. One good precaution to take when agreeing to any work on your car air-conditioning is to check whether the technician has a current Approved Filler Refrigerant Licence. This is a legal requirement for anyone who works on air conditioning systems and handles refrigerant. Make sure that the company concerned is aware of its obligations and complies with regulations.

At Morrison, we have the expertise to help you with any issues you may have with your car air-conditioning or heating. Please do get in touch to arrange an appraisal, we’d love to help you get your air-conditioning up and running properly again. 


Morrison Diesel
30 Selwyn Street, Onehunga 1061 Auckland 
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