Oil Selection for 2015 GTI?

[tired]

May I ask where you got that information about 504 being backward compatible with 502?

He helped develop VW 504

 

[edyvw]

May I ask where you got that information about 504 being backward compatible with 502? I'm considering running a 504 in my CXBB engine for my next change but I am not seeing anything definitive from VW. I have an older repair manual from 2015 that just says VW502.00View attachment 344359

In Europe was backward compatible since 2009. In the US it is since 2017. The US does not have an official TSB; the EU always had. Both oils are minimum 3.5 HTHS. The difference is in the additive pack, and since the US has ULSG since 2017, using VW504.00 is not an issue in gas engines.
The VW switched 1.8 to VW504.00 in 2017-2018.