What PAG oil to use in A/C System?

[Resoom]

I've searched and found no reference to the oil used in the A/C system other than it indicating it's PAG. I see there is an accompanying number on the product label, for example PAG46, 100, 150, ND-8. Just want to get a small bottle to lubricate A/C O-rings/seals prior to installation as I am replacing the Temperature/Pressure sensor.
Thanks!

[Audibot]

http://www.aa1car.com/library/pagoil.htm

Idk which type of compressor the Q5 has, but that list should help you figure out which one you want/need.

Also, if you're opening up the system for a length of time (or it's already open), you should replace the accumulator, and many sources recommend you flush the system before reinstall.

[Smittylube]

Some of the pressure sensors I've Changed have an oring seal, but are screwed onto what looks like an old r12 service port shrader type of fitting and the freon stays in the system expect just a puff.

[Audibot]

Some of the pressure sensors I've Changed have an oring seal, but are screwed onto what looks like an old r12 service port shrader type of fitting and the freon stays in the system expect just a puff.

Same way it is on my B7.

[Resoom]

Yep, took the sensor off last week to look for any visible damage to it, the connector or the harness and got the described "puff", which I've interpreted as pressure in the system so likely and hopefully it's not leaking. The OEM A/C oil doesn't give any specifics as to the number associated with PAG46, 100, 150 etc. so still not sure which one to buy. I believe the OEM compressor is a Denso 471-1502 and when you buy that part (not from Audi directly), the oil is included with the compressor so can't correlate the oil to the compressor. Just need a little to lubricate the replacement o-ring and think since it's not actually going into the system will just get what they recommend at the local autoparts store.

[Audibot]

PAG46 should do you fine!