How to Retrofit Air Conditioning in a VW Passat

Take your VW to a mechanic to recover the R12 refrigerant out of the air conditioning system. A license and special equipment are needed to do this. Because R12 refrigerant is expensive, many mechanics will do the job for free.

Locate the Low Pressure Side connector port by following the larger line from the compressor until you find a black or blue cap marked L or LOW. Remove the cap. You only need to retrofit the system if you see a screw-type connector valve. If you see a quick connect valve, the system already is R134 compatible.

Wipe the connector valve off with a clean towel. This ensures that the retrofit connector properly adheres to the valve.

Put the longer adapter from the automotive retrofit kit onto the port. Tighten it using an adjustable wrench. Place the blue cap from the retrofit kit onto the adapter. This keeps dust out of the system and helps to keep refrigerant in the system.

Find the High Pressure Side service port by following the air conditioning line away from the compressor. Remove the red cap and wipe off the port. Place the shorter adapter onto the port. Twist it using an adjustable wrench until it is securely fastened to the port. Place the red cap from the retrofit kit onto the adaptor.

Fill out the Retrofit Identification sticker provided in the retrofit kit using a permanent marker. Remove the protective backing and place it on the interior side of the hood. This lets future owners and service professionals know that the system has been retrofitted.

Recharge the system using R134 refrigerant. See related eHow titled "How to Recharge Air Conditioning with Freon in a VW Passat."