How long should my car's air-conditioning system last? Are there components which require periodic replacement and is there a maintenance routine to observe?

In Singapore, a car's air-conditioner is switched on as long as the engine is running because of the weather.

The heat-exchanger that transfers heat from the passenger compartment to outside the car - called the condenser - is cooled by a fan that force-feeds air drawn from the immediate surrounding through a matrix of fins and tubes.

While cruising on expressways, the condenser receives much larger quantities of air in addition to what the fan delivers, thus greatly improving the performance of the air-conditioning system.

Modern systems are designed to operate in even harsher conditions than Singapore's, such as in the Middle East where ambient temperatures can hover around 50 deg C.

But periodic maintenance is necessary. The routine should include checking for refrigerant leaks, flushing and evacuating the system of the existing refrigerant, cleaning or replacing the filters, and then recharging with fresh refrigerant.

For passenger cars, such a service is not required on an annual basis but recommended at 60,000km intervals.

Most air-conditioning systems in cars will serve effectively for around 180,000km before requiring replacement of major parts such as the compressor and condenser. That translates to just over 10 years for the average car here.