In a previous thread, I asked if Mobil had dropped the A5/B5 specification from their oils. Tommygunn stated that the change occurred in the summer and is slowly reflecting on the bottles as the old stock runs down. I contacted Mobil but never got a reply. Now, after looking more on the subject I think the reason is that the ACEA 2010 sequences cannot be marketed after December 22nd 2014, although we have seen some wild claims on the ACEA specs I assume that Mobil is at least honest on what they print on the bottle. So my theory is that Mobil 1 and Mobil 1 EP were rated as an ACEA A5/B5-10 and it cannot pass the ACEA A5/B5-12. So now it is only rated as ACEA A1/B1-12. With this in mind I remembered that last year or the year before that on a Pennzoil Q&A someone asked why Pennzoil Platinum didn't get an ACEA approval and they said that the A5/B5 rating cannot be achieved concurrently with the ILSAC standards, and someone else called baloney on this because Mobil and Castrol could pass both standards, and later Pennzoil Ultra got an A5/B5 rating. Now the only OTC oils that manage to pass both specs are Pennzoil Ultra Platinum (if you can find it) and Castrol Edge (both black and gold bottle) but maybe on December 22nd they could drop the ACEA rating (maybe this is the cataclysm that the Mayans predicted). My question is: are ACEA A5/B5-12 and ILSAC GF-5 mutually exclusive? I really hope not because now to get an ACEA A5/B5 you will need to go the boutique oil route. As the ILSAC rating is the more relevant for the North American market.