Affect On Metal
WARNING: This page is about a different car, the 2024 Audi S6 and 2024 Audi A6 Quattro. However, it is still accessible from the selected car via links, so may be relevant.
In its pure state, refrigerant R134a is chemically stable and does not corrode iron or aluminum.
Contaminants, such as chlorine compounds, in the refrigerant however cause corrosion of certain metals and plastics. This can lead to blockage, leaks or deposits on the A/C compressor piston.