I believe the requirements are:
- SAE grade 0W-30, 5W-30 or 10W-30.
- API service SM and ILSAC GF-4.
- Cold pumpability exceeding GM 6094M (30,000 cP at -40 for 0W, 40,000 at -35 for 5W and 50,000 at -30 for 10w respectively.)
- In sequence IIIG, not thickening more than 90%. GF-4 is 150%.
- 13% or lower NOACK volatility. GF-4 is 15%.
- Weighted piston deposit rating of 5.5/10 or better. GF-4 is 3.5 or better.
There are more, these are just the parts I know. It relates to oxidation resistance and deposit control in high temperature situations, such as a high performance engine with no oil cooler.
