In the UK garages tend to use 10w/40 in the Fit (Jazz here). I'd prefer the synth 0w/30 but it's the car of SWMBO, so its not my call. Does 48 Imp. mpg but could do better.....
Buster: where did the quote "Oil analysis can not be used to compare wear characteristics between oils. The biggest problem is that particles greater than 5 microns in size are not detectable using these simple analytical techniques, so an oil which has a more severe wear problem and is...
Hadn't noticed any US made vehicles giving 45 US gallon mpg on diesel, whilst meeting emission requirements. Design goes back to 1999 intro in Europe. The PD was intended to ensure good control and atomisation, beyond the then capabilities of common rail.
Re "I know that your TDI does not have higher valvetrain load then a comercial diesel!!" why do you think that? The TDI has a very heavy load on the injectors, and runs at a higher rpm. HDEO is not tested against VW engine requirements - so any facts to go with your view?
The link is very out of date: In Europe there are 6 current categories of oil types, http://www.atiel.org/downloads/code_practice/AppendixBissue13.pdf Group V "other" including esters, Group VI - PIO (polyinternalolefins, apparently produced by SA and Italian concerns)
As for Amsoil and Mobil...
The VW 506.01 long-life oils are 0w/30, whilst the VW 507 oils are 5w/30. SFAIK, despite the 506.01 being in use in Europe for several years have not given cause for concern. However, VAG give explicit information on the choice of these long life oils depending on the service conditions...
Why? Most PD TDI's (millions of them!) in Europe are run for at least 10,000 miles, and there are no horror stories except when the wrong oil is used. In NA, with ULSD, you're on the same level. None of the UOA show a problem with 10,000 OCIs do they?
With wear on the cams and lifters, its the potential nickel content surely, if UOA means anything? As for the other aspects of 505.01 e.g. "ho-hum" performance - is this opinion or based on fact? It is the 506.01 that have reduced ZDDP, not the old (its not new by any standards, but has worked!)...
Maybe it takes 2000 miles to activate: its out of solution but chemically adsorbed in place in the hot spots. http://www.nsls.bnl.gov/newsroom/publications/activityreport/1998/RU1139.PDF
Started in '68 with a Morris Minor (all of 1098cc) and used 20w/50 mostly, at each fuel stop, to fill up the gaps at the top of the cylinders:) Nope, that didn't work- so it was nearly a total-loss system. But the rust in the sills got to it before the engine gave up entirely.