quote:Originally posted by buster:
Anyone know of why the Europeans use this weight over 30? Mercedes AMG, and all the other european cars come factory filled with 0w-40. This weight I believe has higher shear ability.
I'm sure Mobil does wish all other European cars came factory filled with Mobil 1. I think it's actually only Porsches, Aston-Martins, and the AMG Benzes you mentioned. (I wouldn't be surprised, however, if DaimlerChrysler's new Maybach gets filled with it at the factory, too.)
As far as why this weight is popular in Europe, I can only surmise that it's because a 0w40 oil encompasses what is needed most by hi performance engines, namely, excellent low temp and cold start protection (like a 0 weight oil) as well as excellent hi temp, hi speed protection (like a 40 weight oil).
0w40 seems like a natural progression in Europe since 5w40 has been the "norm" there for quite some time (at least in upper tier oils). Superior base oils (whether Group IV or Group III) are what make 0w40 possible. The shear stability of this weight is evident by the fact that several brands of 0w40 meet Europe's most stringent specs, most notably Mercedes's 229.3. Right now, Mobil 1 0w40 is the only oil of that weight that meets the more demanding 229.5.
The Mobil 1, 0w-30/5w-30/10w-30 don't meet the ACEA A3/B3/B4 tests - these are the most stringent test specs in the world for gas and diesel engine passenger cars. The Mobil 1, 0w-40 is thicker and hence meets these specs.
You can meet these specs with a 30wt synthetic, provided you formulate it towards the thicker end of the 30wt range, ie between 11.0-12.5 centistokes. This way it will also have a high temp/high shear viscosity of at least 3.5 centipoise and meet the ACEA specs ....