At 07:06 PM 10/2/2007, Wesley Pegden wrote...
>Just wanted to follow up on this:
>I just got off the phone with Mobil 1.  The technician I spoke with
>said
>that the 15w50 still had high levels of Zinc and Phosphorus, even with
>the SM rating.  So unless anybody hear knows otherwise, I'm going to
>assume it's okay...

The limits placed on phosphorus and sulphur content by the API SM spec
only apply to weights 0W-20, 5W-20, 0W-30, 5W-30, and 10W-30. None of
those weights are suitable for a VW. There is no limit on zinc, except
indirectly as a part of ZDDP, which is due to the phosphorus limit.

This is found on page 61 of this API document:
http://www.api.org/certifications/engineoil/pubs/upload/1509_16thedition042007.pdf