Getting your car's air con ready for a Brisbane summer

What you can check yourself this week

You do not need tools to get a feel for your system. Start the car, turn the air con to its coldest setting with the fan on high, and pay attention for a few minutes. Try it after the car has sat in the sun, the way it would in a Lawnton car park on a summer afternoon.

If you can see through the grille, look at the radiator-style panel at the front, called the condenser. It sheds heat from the system, and leaves, bugs and grit packed into it make the whole system work harder.

• Does the air get properly cold, and does it stay cold at the lights?
• Is the airflow strong on every fan speed, or weak on some?
• Do you hear any new squeal, rattle or clicking when the air con switches on?
• Is there a musty smell when you first turn the fan on?
• Does the windscreen clear quickly on a wet, muggy morning?

Signs the system is struggling

Air con trouble usually starts small. The car still cools, just not as well, so many drivers put up with it until the first 35 degree day.

Pay attention to the compressor, the pump that drives the system. If you hear a loud noise the moment the air con comes on, switch it off and have it looked at. Running a failing compressor can spread metal debris through the whole system and turn a smaller repair into a bigger one.

Also notice when the problem shows up. A car that cools fine on the open road but warms up crawling along Anzac Avenue in the afternoon is telling you something about airflow over the condenser.

Why a top-up alone is rarely the fix

Your air con is a sealed system. Unlike fuel, the refrigerant (the gas that carries heat out of the cabin) does not get used up, so if the level is low it has leaked out somewhere.

Adding gas without finding the leak is a bit like pumping a slow-leaking tyre and driving off. It feels better for a while, then the problem returns, and the gas you paid for has gone into the air.

The amount matters too. Systems are designed to hold a specific quantity for each car, and too much or too little can make cooling worse and strain the compressor. Moisture getting into an opened or leaking system is another reason a proper repair beats a quick top-up.

Heat makes all of this more obvious. A car parked in the sun at Petrie station can have a cabin far hotter than the outside air, and a system that is only just coping will not catch up before you reach the Bruce Highway.

Why refrigerant work needs a licence

In Australia, handling automotive refrigerant is regulated. Refrigerants can harm the ozone layer or act as strong greenhouse gases if released, and the system also runs under pressure.

That is why it is not a weekend DIY job. Recovering gas properly, repairing the leak and refilling to the correct amount all need the right training and equipment.

Our workshop holds an air con licence, so the refrigerant side of the job is done by people who are allowed to do it. Whoever works on your air con, it is always fair to ask whether they are licensed.

When to book, and what to ask us

The best time is before the heat arrives, not after the first scorcher when everyone is trying to get in at once. If anything above sounded familiar, book now rather than waiting for a humid storm-season week to confirm it.

When you come in, tell us what you have noticed and when it happens. We will find the cause, explain it in plain English and get your OK before any work starts. If we find anything else that needs doing, we send you a video before you pick up the car, and we are happy to show you the old parts.

It is also worth checking your handbook for when the cabin filter is due, as this varies between makes and models. Ask us if you are unsure. We work on everything from small cars to utes, European cars and hybrids.