Volkswagen Golf Service & Repair Manual: Effects on metal

Volkswagen Golf Service & Repair Manual / Air conditioning system with refrigerant R134a / General notes on air conditioning systems / Characteristics of refrigerant R134a / Effects on metal

In its pure state, refrigerant R134a is chemically stable and does not attack iron or aluminium.

However, impurities such as chlorine compounds in the refrigerant do attack certain metals and plastics. This can lead to blockages, leaks and deposits on the air conditioner compressor piston.

Critical temperature and critical pressure

Up to a gas pressure of 39.5 bar positive pressure (corresponding to a temperature of 101°C) the refrigerant R134a remains chemically stable; however, above this temperature the refrigerant decomposes (see Combustibility).

Vapour pressure

In an enclosed container that is not completely full, refrigerant evaporates as vapour at the surface in a quantity sufficient to form an equilibrium between vapour a ...

Water content

Only very small amounts of water are soluble in liquid refrigerant. On the other hand, refrigerant vapour and water vapour mix in any proportion. ...

Other materials:

Detecting leaks
External damage can cause leaks in the refrigerant circuit. Because a small leak will involve only small quantities of refrigerant, leaks should be checked for using an electronic leak detector or by introducing a leak detection additive to the refrigerant circuit. Electronic leak detectors ca ...

Removing and installing mirror adjustment unit
Special tools and workshop equipment required Torque wrench -V.A.G 1783- Note The removal and installat ...

Cleaning off excess adhesive
– Use adhesive remover -D 002 000. 10- as cleaning agent. Observe the appropriate safety precautions when performing this work. WARNING When cleaning the vehicle interior, do not press ...