When the air conditioning stops cooling, most drivers assume it needs a recharge. Sometimes it does, but often the real cause is elsewhere, and a recharge alone just hides the problem for a few weeks.

How your car's A/C works

A compressor pressurises refrigerant, which releases heat at the condenser at the front of the car and absorbs heat inside the cabin. If any part of that loop isn't working, the air coming out of the vents will be warm.

Cause 1: low refrigerant from a leak

A/C systems are sealed, so refrigerant shouldn't run low on its own. If it does, there's a leak somewhere, usually at a seal, hose or the condenser. A recharge without finding the leak means you'll be paying for another one soon.

Cause 2: a failing compressor or clutch

The compressor is the heart of the system. If its clutch doesn't engage, or the compressor itself is worn, the refrigerant won't circulate. Listen for a click when you switch the A/C on. No click often points here.

Cause 3: electrical faults

Blown fuses, faulty relays, failed pressure sensors and damaged wiring can all stop the system working even when everything else is fine. These are often quick, inexpensive fixes once found.

Other signs to watch for

• The air is cold at first, then turns warm on long drives

• A musty or damp smell from the vents

• Water dripping inside the footwell

• A rattling or grinding noise when the A/C is on

• Weak airflow even on the highest fan setting

Simple checks you can do

1. Make sure the A/C button is on and the temperature is set to cold

2. Check whether the cabin filter is clogged, which weakens airflow

3. Look at the condenser behind the front grille for leaves and debris

4. Listen for the compressor clicking on when you press the A/C button

The one fix you shouldn't do yourself

DIY recharge cans are widely sold, but overfilling the system can damage the compressor, and many cans contain sealants that clog components. Modern refrigerants also need proper equipment to handle safely.

How we fix it

We check pressures, look for leaks with dye or an electronic detector, and test the compressor and electrics. Once we know the cause, you get a clear quote before any repair, and we only recharge the system once it's sealed.