Bought a used 2011 Mazda 2 with 50 k miles from a local Chevy dealer recently. They serviced the car of course before the sale. I asked a service mgr. what oil they used, and he said 10 w 30 bulk conventional oil. (Filter is a AC/delco pf 1237) Of course this car calls for 0 W 20 on the oil filler cap. While at the dealer I noticed some of the new Chevys on the lot mentioned they were filled with 0 W 20 oil on the window sticker. I'm just curious if most larger sized car dealers (this one is pretty large) have more than one bulk oil tank underground so that they can buy a couple of different types/weights of oil in bulk.