General Information On Repair

CAUTION: System faults which result in leakage must be attended to immediately to prevent the entry of moisture or foreign particles into the system.


It is important to ensure clean and dry working conditions to reduce the risk of moisture entering the system. Compressor oil must be stored in sealed containers, otherwise the oil will absorb moisture from the surrounding air.

When working on A/C systems, for example when replacing components, open ends must always be plugged immediately after undoing pipe or hose connections.

When carrying out repairs, for example after a collision, it is important to thoroughly inspect every component which may possibly be damaged. Special attention should be paid to brazed joints. Cracked or deformed pipes must not be repaired.

If dirt is suspected to have entered any component, the part must be inspected and cleaned.

Desiccant in air receiver/dryer
The dryer must be replaced when repairing a major leak or replacing a component, or if moisture is suspected to have entered the system. The unit need not be replaced more often than on every third occasion if only minor work is carried out under favorable conditions. Favorable conditions' are defined, for example, as a slow leak (over 24 hours) which is repaired immediately.

Generally, the dryer need not be replaced when replacing a component (i.e. not repairing a leak) if the car is less than a year old or has covered less than 20,000 km (12,000 miles). However, the unit must be plugged within 10 minutes of being disconnected.

Important! Check the type of refrigerant used in the A/C system. This is important to avoid mixing refrigerants, resulting in damage to the compressor and other equipment.

Look in the engine compartment for labels indicating the refrigerant (R12 or R134a) with which the A/C system is filled. It is also important to use the correct type of oil in the system.

R12: Mineral oil
R134a: PAG oil
R12 to R134a (retrofit): Ester oil