According to Mobil1 website M1 5W30 is thicker than M1 10W30 at 100C and has higher HTHS too. The bonus is 5W30 has higher VI. Only at lower temperature M1 10W30 is thicker than 5W30. Why use 10W30 when you can buy 5W30 for the same money and have better oil ?
I think the better M1 30wt is mixing half and half 0W20 with 0W40, the mix has higher VI and HTHS but lower viscosity at cold start. What I have in my E430 is a mix of 5 quarts 0W20 with 2 quarts 0W40 plus 5oz VSOT. The engine consumes about 1/2 quart in 5k miles, it didn't consume any for 10-12k OCI with 0W40.
First number is 10W30, second is 5W30
Viscosity @ 100ºC----- 10.1 --- 11.0
Viscosity, @ 40ºC----- 63.2 --- 61.7
Viscosity Index ----- 146 --- 172
HTHS Viscosity ----- 3.0 --- 3.1
I think the better M1 30wt is mixing half and half 0W20 with 0W40, the mix has higher VI and HTHS but lower viscosity at cold start. What I have in my E430 is a mix of 5 quarts 0W20 with 2 quarts 0W40 plus 5oz VSOT. The engine consumes about 1/2 quart in 5k miles, it didn't consume any for 10-12k OCI with 0W40.
First number is 10W30, second is 5W30
Viscosity @ 100ºC----- 10.1 --- 11.0
Viscosity, @ 40ºC----- 63.2 --- 61.7
Viscosity Index ----- 146 --- 172
HTHS Viscosity ----- 3.0 --- 3.1