A really good informative thread,
To add to it,
A lot of modern oil is built with the emissions factor in mind where it's not how it lubes it's how it burns off, to simplify and especially with VAG a lot of the oils they spec are known as low ash oils whose real purpose is to avoid dpf blockages, the 506 iirc was a PD oil and it did have some sort of mechanical reasoning for it's advised use, iirc it was the cams needed an oil that wouldn't get squeezed out in use such was the high pressure use,
My car 2.0 D4 VEA is shown to require 0/20 oil but I suspect the oil is really spec'd that way due to the brands origins and cold climate,
For many years I've used GM DexosII which is a 5/30 oil and had hoped to continue using it as I get a trade deal on it for £18 for 5L but won't because the extra £30/40 for the oil isn't worth the risk of damaging the engine which again I suspect is that spec to reduce carbonation more than it's lube capabilities .
|