[KTL]

Agree w/Sherwood on the usage of 20W50. We run 20W50 all season (April thru November) in our engines. Early spring it's pretty cold in the morning & same goes for late fall. Sometimes we are "defrosting" the cars first thing in the AM at the track. Never have problems with 20W50 being too heavy.

Re-read the thread again and noticed Chris mentioned he developed an oil cooler leak at cold startup. This should only happen when a t-stat is malfunctioning. The t-stat(s) (some 911 cars have one, some have two) are there to protect the engine-mounted oil cooler and also the external front oil cooler. There's no flow going thru these coolers until their respective t-stats open at 83C (180F)