Originally Posted By: wgtoys
Hmmm, I would disagree. Those same Japanese and American engines when sold in Europe are specified for European style oils. The "Energy Conserving" label is hardly indicative of a big difference: "Those that are at least 1.5% better than a standard reference oil are rated as Energy Conserving."
http://www.roadandtravel.com/carcare/oildetails.htm Wow, instead of getting 20 mpg I might get 20.3 mpg. Hardly an earth shattering improvement, and GC is going to give excellent wear protection in those Japanese and American engines you are concerned about.
European specifications must accommodate very high speed operation for long periods of time (Autobahn) with consequently high oil temperatures. It isn't surprising that European oil specs tend to favor higher HTHS ratings at the expense of the modest energy saving of a US style oils.
Please provide evidence of a Japanese engine specfying 0W-30 European formula oil (or any 0W-30). I am not talking about using a 5W-30 where a 5W-20 is used in the US (that may be acceptable), I am talking about a European formula 0W-30 specifically designed for certain VW, MB, and BMW engines.
I am not advocating you use an energy conserving formula just to save on gas. There are other factors involved. The lack of energy saving formula is just one indication that it may not be suitable.
In previous threads, I have suggested that using 5W-30 may be OK where 5W-20 is preferred by the auto manufacturer (so long as they only "recommend" 5W-20 and also allow 5W-30), but using GC 0W-30 is whole other ballgame IMO. This only applies to late model cars, and not the ones with lots of mile on them that many on this forum drive.
If you engine specifies any of these specs (that CG) does not have then you should not use it:
GM 6094M, GM 4718M
Ford WSS-M2C929-A
Chrysler MS-6395
ILSAC GF-4 energy conserving
ACEA A1/B1