DaveW thanks for the heads up on the heat exchanger. I guess in terms of oil cooling it would be a toss up relative to temp differential of both fluids as to whatever advantage might be found in transferring extra heat to the coolant via the oil when the engine is running at max temps..? I guess there will be a tipping pointand someone with better brains than I has worked that out...Hopefully..(-:
As I suggested I might imagine that heating the oil as quickly from cold might be the primary purpose... Though I have been wrong before..!
Next time I run the 991 and get it up to temp I will try to find out id indeed the expansion tank cap just spins, or if it begins to unscrew....Interesting topic this, thanks guys. Every day is a schold day...(-:
