It is a closed system but also has a mechanical seal on the compressor, so open driven, which relies on oil lubrication to seal it and periods of inactivity can cause it to leak. The same with rubber hoses and o ring seals . These can cause issues with ageing .
If you have a continual issue with leaks then a pressure test is the real way to deal with this. Slower leaks are usually on the evaporator / low pressure side and faster leaks on the condenser / high pressure side.
It would interesting to see how you change the oil on a compressor on a car. Draining oil and refilling has to be precise as overfilling can cause hydraulic issues and compressor failures. The issue with garages injecting dye and oil every time they do a recharge is crazy. They dont know how many times this has been done and a recipe for disaster.
All staff using refrigerants 'should' be Fgas certified. We have lads who work for us and although they have experience for working on A/C systems wont be allowed to install , attach gauges or decant refrigerants without being overviewed by a qualified engineer until they have passed. I have 1 lad in next week for his week of training. But and this is a big but, the geezers at kwik places have the required certification to use refrigerants but that doesnt make them a qualified and life experienced engineer to understand the real way all the components work and what to expect when something goes wrong. Sadly these 'budget' recharges mean feck all. Yes, shout that you had your car recharged at a local £30 a job place and it works. It may well do, but correct methods employed will mean it is leak free and safe to use and they wont offer this. As for the buy a bottle job and install, then they dont mention fitting without air and moisture in the hose lines and that can cause many issues, let alone frost burn and environmental issues from mal using. I am sure some have 'vented' into the atmosphere and think 'don't care' , but this is a part of the larger scale of the world around us. We are getting cleaner with refrigerants , but some of our cars are using old skool stuff which isnt as green.
Please, please think of the environment, long term value and use a company that knows what it is doing than just a bloke with a machine and a £30 bargain every year . We all like a bargain and while it may seem a value thing to do. if it doesn't work, they would be clueless to follow the process of diagnosing the fault as not all cars need recharging and could still be a simple fault, such as a relay, fuse or control that was the real problem. They would potentially still want paying even if the recharge doesn't work.
North West Surrey
