My point is that at operating temperature there shouldn't be any real difference between 5w40 and 15w40, it's the 40 that matters, not the 5. The 5 absolutely matters at low temp and back when I was regularly commuting in a 240D I couldn't have managed it in the winter with 15w40 conventional oil, the car wouldn't have started in the cold. Even with 5w40 when it was really cold things got iffy.There is no reason you can't use 5w40 and Mercedes specified it in the chart in the manual... Curt
Sent from Yahoo Mail on Android On Fri, Aug 9, 2019 at 12:55 PM, fmiser<fmi...@gmail.com> wrote: > Curt wrote: > I still don't think you understand how the 5w part of the rating > works. It's a 40w oil that resists thickening when it's cold. Other way around. It's a 5w oil that doesn't thin as much as it gets hot. Until the VI breaks down and it becomes a 5W oil. Admittedly not prone to happening without longer drain intervals. > The Delvac 1 everybody used to crow about was 5w40... Some of the group IV synthetic oils don't even need viscosity improving to achieve a multi-weight rating - they are by nature less prone to thinning as it heats. _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
