There is a veritable laundry list of generally permissible viscosity classes, all meeting "API SF ACEA A2, or better". There are minimum temperatures listed, with no upper temperature limit published for any grade. I'm not one to put too much thought into fluid requirements beyond checking the manual, but this relatively huge list is somewhat perplexing to me.
BMW recommends Castrol (I get it, marketing agreements and all that, but lemme finish), and Castrol recommends Power RS 10W50. The PDS on that product isn't terribly impressive to me when compared to the PDS of TDT 5W40 (one of the permissible grades, and I scored 5 gallons of it for $13/gallon a while back). TDT actually has a higher HTHS, 3.7 VS. 3.8. The JASO MA rating of Poker RS is of no importance to me in this application.
The chin scratcher here is: should I hold the TDT as a winter fill, and use a heavier grade for summer time, or just use up my hoard of TDT and then go from there?
BMW recommends Castrol (I get it, marketing agreements and all that, but lemme finish), and Castrol recommends Power RS 10W50. The PDS on that product isn't terribly impressive to me when compared to the PDS of TDT 5W40 (one of the permissible grades, and I scored 5 gallons of it for $13/gallon a while back). TDT actually has a higher HTHS, 3.7 VS. 3.8. The JASO MA rating of Poker RS is of no importance to me in this application.
The chin scratcher here is: should I hold the TDT as a winter fill, and use a heavier grade for summer time, or just use up my hoard of TDT and then go from there?