One more thing, Daisycutter also posted on a oil discussion in the Passat b5 forum in vwvortex. The title is "5w-30 or 5w-40 oil discussion". His summary of his analysis was:


The results were fine, except that this oil needed to be changed at 5,000. I wouldn't push it past 5,000 in the future based on the results. If Amsoil 5W-30 was on the way out at 5,000 (bear in mind that this is a 25,000 mile oil) then I wonder what some of the 5W-30 dino oils would look like under similar conditions? Perhaps fine, but I'm not gonna find out for myself. I think I'm gonna try lubro-moly at the 25,000 mile change and get that tested. It's only $5 a quart and if it looks good at 5,000 I'll stick with that, nothing against Amsoil. I'm gonna stick to the 5,000 mile interval for now regardless of the extra expense of synthetic and go with 5W-40 for future changes. If lubro-moly is holding up well at 5,000 I'll check it again at 7,500.