Originally Posted By: redrocker55
Thank you for the responses guys...
So now that I know how to post...here is the entire history of my engine so far. All UOA are via Blackstone.
The factory fill was rumored to be Fuch's 5w40.
The second UOA was German Castrol.
The third UOA was AMSoil Euro 5w40.
Each subsequent UOA was the AMSoil Euro also.
Of all the UOAs posted, it looks like GC provided by far the best numbers. I'm wondering why you would settle on the AMSoil instead of GC? GC is at least on the VW approved 502 list. It doesn't matter what AMSoil says, if it's not on the VW list it isn't warranty approved, and you'd be chasing AMSoil for an oil-related warranty repair rather than VW.
I'm a little paranoid about this these days - I just picked up my 2007 Audi S4, 4.2 V8, from the Audi dealer last week - with 2 months remaining on the 4 year warranty, Audi authorized a full long block engine replacement due to excessive oil consumption. Total cost of the dealer performing the long block replacement if not covered by warranty would have been around $18K.
Also for what it's worth, I'm using Castrol SLX Longlife LL03 on my 2010 S5 - it's a VW 504 rated oil, which is warranty compliant for 502 specified engines, and as a low SAPS Euro IV oil it is supposed to create 40% less intake valve deposits in direct injection engines, according to a Lubrizol study referenced here. I have done a lot of reading here, and believe that a Euro IV low SAPS oil is critical to reducing these deposits.