Car air conditioning in summer: symptoms not to ignore

Around here, air conditioning is not a luxury. Between June and September, cars spend hours in the sun and cabins can reach temperatures that damage plastics and make driving uncomfortable. Most faults give you warning first.

It cools less than last year

This is the most common symptom, and one drivers often misread. A sealed system should not lose a noticeable amount of refrigerant, although gradual losses can occur. If the charge is low, check for leaks before recharging; topping it up without finding the cause could mean paying twice.

Before recharging, check the cabin filter, the condenser in front of the radiator, which can collect dust and salt on the coast, and whether the cooling fan cuts in as it should.

A damp smell when you switch it on

The smell often comes from the evaporator: moisture left behind, mixed with dust, can encourage bacterial growth. You may also notice the windows misting more than usual. A technician can clean the system and replace the filter; if it has been through two summers, it may be contributing to the problem.

Water dripping inside the car

Water in the footwell can come from a blocked evaporator drain, but you should also rule out water entering from outside and problems with door or window seals. If condensation cannot drain away, it may enter the cabin. The repair is often straightforward, but leaving the carpet damp can lead to a persistent smell and corrosion beneath it.

Noise when the air comes on

A click when the system engages, or a new noise that appears when the air conditioning is running, can come from the compressor clutch, belt tensioner, a pulley, the compressor or another component. Have unusual noises checked early, as compressor failure can be one of the costlier repairs in the system.

What a normal check covers

• Outlet temperature at the vents and overall system operation.
• Cabin filter and the condition of the evaporator.
• Condenser, fans and cleanliness of the front end.
• System pressures and leak testing, using dye where appropriate.
• Belt, pulleys and compressor operation.

One habit that extends the system's life

Run the air conditioning for a few minutes in winter too, about once a month. Regular use helps keep the compressor and its oil moving, although the exact requirements vary between vehicles and compressor types. Long periods without use can leave faults unnoticed until the first hot spell. Before parking in the sun, let the hot air out for a minute with the windows down; this can reduce the initial load on the system.