This thread does bring up an interesting point. One of our Canadian members posted a picture showing a glass of GC 0W30 and a glass of AC (American Castrol) 0W30 and the GC was MOST DEFINITELY GREEN and the AC was amber. My GC is amber with a green layer on top, NOT DEFINITELY GREEN like the post. I'm betting the oil posted was from the T/W batch, not the TAG 785 batch (that's the batch from which all my GC has come). Hm-m-m-m, (you know like, hm-m-m-m) wonder if there is a difference (source, formulation, etc)?