The deed has been done.
My game plan was to use Quaker State Ultimate Protection 5w-30 - it seemed like a good, cost-conscious choice that I've used in the past. However, it appears that this line has been axed. It's out of stock at every Walmart I've checked. I instead settled for Castrol Edge 5w-30 SP in the black bottle (not the "good" stuff) which was on sale.
Shaking, and with tears in my eyes, I poured a non-BMW licensed oil into an engine for the first time in years. I was stricken with grief thinking about how disrespected my car must feel running this crude, American excuse of a lubricant.
Sarcasm aside, I just took it for a test drive. It runs smoother as I've found this engine does with a lower viscosity oil (this is not unique to this Castrol of course, I just notice it tends to chug a tiny bit more at very low RPM with 5w-40 vs 0w-20, and more of a bump when starting the engine at speed).
I'll take a sample when I change this fill out. Unfortunately, I didn't think to take a sample when draining out my old fill of ESP - I was changing my oil in a hotel parking lot and therefore trying to prioritize speed...
