Oil

fishmens67 said
My factory 1973 W200 360 93000 miles 60 cold and 45 hot at idle rebounds quickly to 60 hot.
20w50 during the summer and 10/40 during the winter since 1983.

Quite respectable with factory tolerances. Would probably also be just fine with 10-30, ‘cause you don’t need 45 psi at hot idle.