A4-Banker

Seem like audi needs specific refrigerant oil when charging the AC system.

This is what I did to find out which AC recharge can should be compatible with my audi (B6 Audi A4, 3.0L):

Most accurate way: get underneath the car, check the location of the AC compressor to find out the make and model.

My compressor label mentioned ND OIL 8.

If compressor label doesn't mention oil type, try finding out the type of oil based on the compressor model #.

Did some research on ND Oil 8 and found out that PAG 46 is compatible with ND Oil 8.

You can use this table from Johnsen's R-134a OEM A/C Lubricant Specifications to check the compatibility

See link: http://www.johnsens.com/uploads/file...cantguide4.pdf

If somehow you are out of luck and your audi AC compressor has no label or feel lazy to get underneath the car, your best bet is to use an educated guess to pick the correct charger can....or just go to a professional shop / dealer.

Easy Way (but not most accurate):

Use the Low Pressure Service Port Finder Tool that rechargeac.com has on their website
Link Low Pressure Port Finder tool for Car A/C Recharge

Put in your make, year etc and you will get the AC Compressors used for your Audi model. Maybe all compressors for you year and model used the same type of oil, so that will take out the guess work of finding out which AC compressor you have in your Audi.

So now when you select you R134a refrigerant recharge can, you can pick the one with the correct AC oil type. Should help to avoid any future problems and headaches down the road.