Originally Posted by TVT_DESIGN
5W id thicker then 0W, MB has actually switched over to using 5W30 on all of their vehicles.
The pic above is of it installed on the car.
Temps have dropped about 45 degrees. It is in the 190 range. This is with normal driving. Once we track it we will have a better idea of the effect.
The problem is that the first number is the cold viscosity of the oil and the latter is the warm viscosity. The warm viscosity is the most important, so if you are worried that 40 weight is too thin, you should move to a 50 weight oil with a small cold weight, like 0w50. Once the engine reaches operating temp, the 5W is no different than the 0W. I guess I'm confused at why you move to such a thin oil. I;m guessing becuase the car stays much cooler than stock? Have you noticed an increase in engine responsiveness with such a lightweight oil.
190 is pretty darn cool! I was driving BMW's all weekend and spent some time with the 3.0tt motor and those cars were hovering just below 250 degrees during normal and enthusiastic driving. Damn those motors are wonderful! Too bad the price tag associated with cars with that motor is a bit prohibitive!