That's exactly right. Two list members who tried the 0W-40 had lifter noise return on their OM603 engines, and one noticed a significant increase in iron wear particles in the oil analysis. Reverting to 5W-40 or 15W-50 cured both issues... lifters quieted down and iron wear went back to normal.
Another use for thin oil is in search of peak power. Racing engines are sometimes fed watery thin stuff like 0W-20 which will give a percent or two peak power gain over thicker oils. But those engines are also torn down way more often than our street engines. I'd say AMG and Porsche specify the 0W-40 because it's a compromise between peak power & MPG (super thin) and best protection/longevity (relatively thick). YMMV, I'm not saying it's bad oil (it's not), just that for MY engines I perfer Delvac-1 5W-40 (aka M-1 T&S). =) -dm > ------------------------------ > Date: Thu, 25 Aug 2005 20:30:13 EDT > From: [EMAIL PROTECTED] > Subject: [MBZ] 0W-40 > >>> I think the 0W-40 is used as factory fill for fuel economy, >>> not for protetction... I wouldn't put it in my cars. > > For fuel economy? Please explain. And keep in mind that low-performance > slowpoke cars like the SL55 and the Porsche 911 Turbo use M1 0W-40. > But it's not "safe" for your stuff? > > RLE/ Seattle
