Fault-Tracing, Repair: Equipment

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

A/C stations

To satisfy the legal requirements and to allow rational handling, Volvo has developed A/C stations which can be used to:

empty the system and clean and recycle refrigerant.
vacuum pump, check seals and top up the system.

The instructions for service and maintenance of the A/C station must be followed carefully so in order for it to function correctly.

CAUTION: Different refrigerants/oils must not be mixed. Therefore equipment adapted for the relevant refrigerant must be used. Otherwise there is a risk of damage to the equipment and to the system in the car.

Draining the system

The system (car) should have a temperature of at least 20°C (68°F). In cold climates the car should be taken into the workshop the evening before the work will be carried out.

The drainage time is reduced if the A/C system has recently been running and the engine is hot (radiant heat).

Vacuum pumping, leak testing the system

Any topping up of the oil in the system must be carried out prior to vacuum pumping.

This primary aim of vacuum pumping is to evacuate any moisture from the system. The low pressure means that the water evaporates and can then be sucked out of the system.

To ensure that all moisture is removed from the system, it is important that vacuum pumping continues for at least 50 minutes . In humid climates this may take even longer .

This other reason for vacuum pumping is to check that the system is sealed. When pumping is complete, the negative pressure may only be reduced minimally for approximately four minutes.

CAUTION: Water that is sucked up by the drying agent cannot be extracted by vacuum pumping.

WARNING: Compressed air must not be used under any circumstances to leak trace a system with R134a. A mixture of air and R134a is explosive at high pressure and high temperature.

Topping up the system

Fill with the correct amount of refrigerant (the amount depends on the car and model year etc).

Too much refrigerant reduces the capacity. In addition there is a risk off refrigerant in liquid form reaching the compressor with increased wear/incidence of breakdown as a result.

Too little refrigerant reduces the capacity. In addition there is a risk off poor compressor lubrication (lack of oil) with increased noise/wear/incidence of breakdown as a result.

Leakage test

In addition to the vacuum method (vacuum pumping) a supplementary test must be carried out with a leakage locator after the system has been opened.

NOTE: The leakage locator must be adapted for refrigerant.

On hoses with PVC casing the casing must be removed and the hose with connections must be wiped clean prior to leak tracing.

This is because refrigerant diffuses (= forces its way out) through the hoses. The small amount that forces its way out is then collected under the casing and this amount may be sufficient to affect the leakage locator.

Performance test

After the system has been opened, a performance test must be carried out to check the function of the system and its capacity.