M1 5W30 thicker than 10W30 at operating temp ?

[HTSS_TR]

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

 

[Quattro Pete]

Originally Posted By: HTSS_TR
Why use 10W30 when you can buy 5W30 for the same money and have better oil ?

Theoretically, the higher the viscosity spread, the less shear stable the oil, so maybe the 10w-30 is more shear stable? I say maybe, because that does not always hold true.

But in general, I agree, between the two, I'd get the 5w-30.

 

[Sonataman]

What continues to perplex me is how a 10w30 can be thinner than a 0w40 at 40c!

The oils you mention are BARELY thinner than a straight 20 at 40c, while the 10w30 and 0w40 are thicker than the straight 20!

Instead of the 40C, they should list 0 and 100C and THAT would clear up the confusion that is motor oil!

 

[Quattro Pete]

Originally Posted By: Sonataman
What continues to perplex me is how a 10w30 can be thinner than a 0w40 at 40c!

Because the first number has nothing to do with viscosity at 40C. Need to look at MRV or CCV numbers to reveal the whole story there.

 

[chubbs1]

I am not sure why anyone would but the 10w30 (price being the same). I also would not hesitate to mix the 0w20 and 0w40 if I had a vehicle out of warranty.

 

[Eddie]

In addition the 10w30 has a lower NOACK value.

 

[HTSS_TR]

Honda recommends 10W30 (dino but syn is okay) for S2000 in warmer climate and 5W40 in colder area. The S2000 was developed late 1990's and at that time dino 10W30 was much more shear stable than 5W30, forward 10-12 year until now the SN 5W30 is very shear stable, no need to use 10W30, specially the M1 10W30.

My next S2000 oil change I will mix half&half M1 0W20 with 0W40, may be a 3-2 ratio of 0W20 and 0W40.

 

[mechtech2]

Viscosity is a range, not an exact position.
So that explains it all.

 

[CATERHAM]

This disparity has come up for discussion before.

Oil's with the same HTHSVs and the same VIs will have the same operational viscosities at all temp's from 150C down to at least 0C. Since M1 10W-30 has a much lower VI that should compensate for it's lower HTHSV.
At normal hot operating temp's (say 100C) I would predict that their operational viscosities will be much the same. At lower temp's that's when the difference in their viscosities will be most apparent.