No sweat. We'll get to the bottom of all this before too long. As you've no doubt picked up by now, you've wandered into the ultimate BITOG mine field.
Yeah, that's pretty much how they all operate. I delivered parts for a parts store for a year. They were bought by Carquest about a month before I left. Nothing changed except for the white Wix filter boxes changed to Carquest blue boxes with Wix filters inside. Most, if not all, of the oil on the shelf was probably around from the time the store opened. Collecting dust. Some of the belts and exhaust parts looked like they were older than the store itself.
I'm really starting to think that this "AC" doesn't exist. No one has come up with any substantive evidence and the serial numbers are all wrong. Why would Castrol suddenly start to make 0w-30 with serial numbers that are out of sequence? And another thing: I don't recall seeing serial numbers on the bottoms of the bottles of domestically made Syntec (5w-30, 10w-30 etc.). If 0w-30 is now made in the U.S., wouldn't Castrol stop putting serial numbers on the bottle? There may be a light at the end of the tunnel, however. The AZ in DeKalb usually has the most recent variant of GC because someone besides myself buys the stuff in quantity. So if there is AC, it should show up at the Dekalb AZ soon.
Castrol prints batch numbers on every Syntec bottle, regardless of grade.
I agree. As to the "M13..." thing, I've written that off as erroneous reading. I've seen a fair number of bottles that have compressed or smudged, or otherwise hard to read numbering. I'd bet that bottle was really an M03... bottle (green, btw!) misread. I have seen other Castrol products with the same or similar serialization scheme appearing on the bottom of the bottles, so no, they wouldn't stop doing this with "AC" if it existed.
