A/C System Components
CAUTION:- 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.
- 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.
- The 0-ring must always be renewed if a system joint is opened. It is important to use the correct 0-rings for the different refrigerants. A blue 0-ring must never be used for R134a. On the other hand, a yellow 0-ring may be used for R12.
- When replacing a component, the new component must be filled with the specified quantity of oil. Too much oil will impair cooling. Too little oil will cause damage to the compressor.
GENERAL INFORMATION ON REPAIR AND REPLACEMENT OF A/C SYSTEM COMPONENTS.
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.
Topping Up Lubricating Oil
- 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
For more information refer to specifications for particular component or system.
- The oil must be topped up when repairing a leak or when replacing a component. The quantity required for the component in question will depend on whether leakage has taken place slowly or quickly. Rapid leakage (e.g. hose rupture) often means that lubricating oil escapes with the refrigerant. Slow leakage (longer than 24 hours) does not normally means a loss of lubricating oil.
- The following applies when replacing a compressor. Drain and measure the quantity of oil in the original compressor. Also drain the new compressor completely. The new unit should then be filled with the same quantity of oil as that drained from the original unit.
CAUTION: The compressor should always contain at least 50 ml (1.691 oz) of oil regardless of the quantity drained.
If x ml (oz) have been drained fill with x ml (oz)
70 ml (2.367 oz) 70 ml (2.367 oz)
30 ml (1.014 oz) 50 ml (1.691 oz)
50 ml (1.691 oz) 50 ml (1.691 oz)
15 ml (0.507 oz) 50 ml (1.691 oz)
- The following applies when replacing other components. Drain and measure the quantity of oil in the component which has been removed. Fill the new component with the same quantity of fresh oil prior to installation.
Use Correct 0-rings (Colors) As Follow
R12 BLACK (no longer used)
R12 BLUE
R12 and R134a YELLOW