Originally Posted By: OVERKILL
Originally Posted By: umungus1122
In the case of 30w, would this mean the oil with the highest VI would give the best high temp. protection, regardless of HTHS as say in a thicker 30w like a Euro spec. 30w?
No, HTHS IS the high temp protection, hence the HT in HTHS.
He said the engineer didn't know that the M1 10w-30 had a lower HTHS than the 5w-30 M1. and the 5w-30 higher VI was the reason it would protect better. If he didn't know the 10w-30 had a lower HTHS, what if it had a substantially higher HTHS than the 5w-30? Do you see what I'm saying, if he had no knowledge of the M1 10w-30 HTHS, why did he claim it was the VI alone?