That is a pretty cool find, Daox. I wonder if the main purpose is actually to
cool the oil once up to temp, though. Engine wear/longevity is improved if you have a way to keep your 5W30, 5W20, and now 0W20 oils from getting too thin with a hot engine. In the earlier cars you mention, the VIIs of the time may have been one of the concerns driving this inclusion, as high heats are murder on them.
But since oil temps lag coolant temps during warmup, it is a nice way to get a little more heat into the oil sooner. Pretty slick.
