You probably don’t think much about your car’s air-conditioning or climate control system, it just sits there doing its job with most of its working parts hidden from view, but the fact is it does have working parts which need occasional maintenance to prevent them wearing out.
Your car’s aircon system works using essentially the same mechanism as your kitchen fridge, and your car has similar components to a fridge under the bonnet and behind the dash – a compressor, condenser, evaporator, and lots of piping (but no salad drawer).
If your aircon seems ineffective or stops working altogether, the most likely cause is a low refrigerant level – this is where you need to “recharge” or “re-gas” the system. The aircon system works by converting a gas to a liquid and back again, and over time small amounts of gas escape through microscopic gaps in the pipes and seals – this is the gas that needs topping up during an aircon service. Cars can lose up to 20% of refrigerant gas per year.
Of course if any of the pipes or components are actually broken, the aircon system will very quickly stop working as large amounts of gas escape; if this happens we will need to check the whole system for leaks and damage, but more often than not a re-gas will get your aircon back up to full coolness.
Aircon should be checked every 2 years; you may not notice a problem but if you let the system run low on refrigerant the compressor has to work twice as hard and will therefore wear out in half the time. A new compressor is much more expensive than an aircon recharge.
To keep your aircon system in good condition it should really be left on all the time, this prevents the rubber seals and gaskets from drying out and cracking, and thereby causing leaks. Run your system for a few minutes every week at the very least. Contrary to popular belief it does not greatly reduce your mpg, unless you do a lot of very short journeys and few long ones.
If you notice a distinct smell when you switch on your aircon, it’s probably micro-organisms that collect on the evaporator behind the dashboard, and are then blown into the cabin by the fans. These can cause allergic reactions, coughs and sore throats – we can treat the system to kill off these nasties so do let us know when you bring the car in for its aircon recharge.
Considering a DIY re-gas? Aircon gas ‘top-up’ kits can be bought from motorists shops, but are very much NOT recommended. Firstly your aircon system is pressurised and filled with gas, unless you’re a former mechanic or rocket engineer you should really not be messing around with it at all. Secondly they won’t do a complete job anyway – we remove all moisture and contaminants from the system prior to re-gassing, your DIY kit will leave this behind.
Leave it to the experts. Aircon re-gassing is not expensive, why not add it to your regular service routine so it doesn’t get forgotten and end up leaving you hot under the collar…