My go-to mono-grade SAE40 for years has been Duron40. Because of it's high VI, I trust it down to -5C/20F.
I also use it to give 10W30 a HTHS boost, and as a top up oil.
Synthetic 10W40 and 15W40 synthetic blends, from the KV100C to published HTHS trajectory, suggests that they are VII free.
HDEO SAE40 is available in "full saps" examples: Mobil 1640 and Delo 400, medium saps examples: Shell T-1, Mobil 1340, Duron SAE40,
and low saps: Mobil 1240 and Delo 100.
AS per SAE rules, VII free 10w40 and 15W40 engine oils could be labeled as SAE40, and therefor, are mono-grades in disguise.
I also use it to give 10W30 a HTHS boost, and as a top up oil.
Synthetic 10W40 and 15W40 synthetic blends, from the KV100C to published HTHS trajectory, suggests that they are VII free.
HDEO SAE40 is available in "full saps" examples: Mobil 1640 and Delo 400, medium saps examples: Shell T-1, Mobil 1340, Duron SAE40,
and low saps: Mobil 1240 and Delo 100.
AS per SAE rules, VII free 10w40 and 15W40 engine oils could be labeled as SAE40, and therefor, are mono-grades in disguise.