cobalt

I have a copy of TSB 1701 regarding Porsche approved oils. The TSB states that these oils are good for any model from 1984 on. I have read so many conflicting opinions on this.

Does anyone have a definitive answer on weather 0w-40 should be used on earlier cars like my 93 GTS, 93 964 C2 or my 94 turbo? I usually use 15w-50 M1 but now I am being told I should switch to 0W-40. Why is it I feel that this should apply to the newer cars and not the older air cooled 911's?

srf506

Porsche, and the other manufacturer's are constantly monitoring the composition of various oils. Evidently, there has been some change in the makeup of all of the "normal" oils and viscosities we are used to using and have grown to love/hate (Sulfer, phosphate or something) . So, in its infinite wisdom, the factory has decreed that the latest formulation of Mobil 1 0w-40 is now closest to what they believe will make the car perform the best, with the best lubrication and cooling properties. Whether you believe them or not is a choice only you can make. Personally, I still run Mobil1 15w-40 in my 85 euro 930 and 84 euro Carrera 3.2. However, in the 2002 996TT I run 0w-40 Mobil1. Maybe at the next rebuild I'll switch one of the older cars over, but until then, I'll stick with what I got.