Since 10W50 just isn't really available. I have pretty much always used 15W50 but don't we at least, theoretically, want that first number as close to zero as possible? Correct or no?
Wow! A thread about engine oil...great! Shell 5w40 in both 328; no leaks, very satisfied so far. Rgds
The first number is the cold viscosity. I would think in AL, really cold starts and initial cold operation would't really be an issue; at least between the months of March and November. I don't have the manual in front of me and I can't remember what the original spec was, and I realize oil has evolved since the manual was written but I thought 15W40 was the original oil spec so if that's the case 15W50 would work fine. I'm sure someone will correct me if I am wrong on that. -F
10W50 is called for in the manual. Was 5W or 0W even available in 1983? I'll just stick with what I have been doing and save the 5W for my daily drivers in the winter.
You are on it, Dr. Tommy. IMO our older engines do benefit from the 50W and my oil pressure drops on the lower weights. The first number is actually "flowabiity" and the lower the better, so the 5-50W would be the modern equivalent. Of course in Texas in the summer I can dump Royal Purple 20-50W in everything and go for it! I think Mobile 1 even goes to a 0-50W now... Now, a newer engine, even a 328, this is void advice. Go with your manual, and maybe adjust for the number of miles on your engine.. YMMV
Ha! Love to see old times threads come alive! My 328 gets 10W60 Shell Helix racing full synthetic. Because times are changing, and dino oil isn't that good anymore...
..and your oil pressure is pretty good with that I would think? Absoultely agree on the modern molecules!!
That's the out of the bottle number... With an older car esp. carburated, the blow by at the rings starts diluting it almost immediately. You know, in the real world...where they actually run..
Here's the spec: Fully-synthetic ester formula for passenger cars, light trucks, performance vehicles and marine applications Excellent wear protection and friction reduction across a wide range of operating conditions High detergency allows extended drain intervals and provides increased cleanliness Improved fuel economy and ring seal for more power Superior high temperature stability and oxidation resistance increases lubrication of hot metal compared to other synthetics High natural viscosity index (VI) provides thicker oil film in bearings and cams Less evaporation than other synthetics for improved efficiency and ring seal All products are completely compatible with other conventional and synthetic motor oils, Image Unavailable, Please Login
