Castrol Edge will have a Dexos approved oil soon. When I rang their technical phone number, the bloke was happy to have a chat but definitely towed the company line and said they can't recommend using any of their products until their new Dexos oil.
We also chatted and laughed about how much bloody money GM was making getting certification from all the oil companies. It must be very costly having to have products certified to API and/or ACEA and/or ILSAC and now all the manufacturers own certifications.
I've gone with the Edge 5w30 ACEA A3/B4 as that european standard is more leaning towards motor protection than fuel economy and emission system longevity, than ILSAC or Dexos tend to be.
I only swapped out the Mobil 1 0w40 for the 5w30 to see if it was causing this ticking noise I get when warm. It wasn't the cause, and I'm pretty sure it relates to the factory tune as it only ticks when its filled with 98. No idea why its doing it (any idea
@monstar ?)