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:

Basics for working on refrigerant circuit
Observe instructions specific to the workplace; → Volkswagen ServiceNet; Handbooks; Service handbook; Environmental protection. Refrigerant from air conditioning systems / refrigerant oils - to be displayed at refrigerant designated working are ...

Removing and installing headlight dipped beam bulb (dual halogen headlights)
Note Left headlight dipped beam bulb -M29- and right headlight dipped beam bulb -M31- are only fitted on dual halogen headlights. Removal and installation are described for the left side. Removal and installati ...

Balancing wheel, balancing wheel on stationary wheel balancer
Before you start balancing the wheels, the following requirements must be met. Tyre pressure must be OK. Tread must not be worn on one side. Tread depth should be at least 4 mm. T ...