The oil must meet the VW 502.00 spec to be compliant with warranty requirements. These oils can be in various weights... usually 5w-40, but there are others such as Mobil1 0w-40 or Casrol Syntec GC 0w-30.
Generally the oil should meet the VW 502.00 spec. The viscosity grade could be 5W-40, 0W-40, 0W-30, or 5W-30, but in all cases the HTHS viscosity would be >3.5 cP.
Mobil 1 0w-40 would be nice, but Syntec 0w-30 would be The BOMB in terms of getting something special that still meets warranty specs. AutoZone and PepBoys has it.
Originally Posted By: Audi Junkie
Although VW 502 is an old spec, VW 504 does not really add anything that I am aware of in performance criteria, just low sulphated ash.
How is VW 502 "old" despite its specs getting regularly updated?