I remember reading someplace that Mobil 1 (and perhaps all synthetic
base stock oils) start out with the thicker weight (50 in 15w50 for
example) and don't have viscosity modifiers due to being at a more
consistent viscosity from hot to cold. Don't quote me on that, though.
;)
M.B.
> -------- Original Message --------
> Subject: Re: DML: RE: Mobil One oil
> From: jon@dakota-truck.net
> Date: Wed, February 16, 2011 10:09 am
> To: dakota-truck-moderator@bent.twistedbits.net
>
>
> Barry Oliver <barrysuperhawk@comcast.net> wrote:
>
> > Just as a Data point, having extensively tested my oil at every oil
> > change, I can conclusively tell you the 15W50 is in a whole different
> > league than the other 5 and 10 weight oils. For example, in my truck
> > [99, 318, 150k], after 5k miles of mixed driving, both the 10w30 and
> > 10w40 are completely done for, and come out like water. the 15w50
> > however is only at about 1/2 life according to blackstone, and would be
> > good for a 10k interval according to them. Their newer 5W40 "truck and
> > SUV" oil seems to be made of the same base stocks/additives as the
> > 15w50. So, the only two oils that go in my truck are the 5w40 and the
> > 15w50...
>
>
> I'm surprised to hear that - I would have expected the viscosity
> improvers that have to work across a wider range (15-50 vs 10-30) to
> wear out much sooner, especially given that the engine oil weight
> scale is logarithmic, not a simple straight line. (The jump from 20
> to 30 is much bigger than the jump from 10 to 20.) So, the expansion
> required from the viscosity improvers to cause a 15 weight oil to act
> like a 50 weight at temperature or a 5 weight to act like a 40 weight
> is considerable! Must be there is something very different between
> the oils than just the viscosity improvers. As you suggested, perhaps
> the base stock or additives.
>
> At any rate, that's good info, thanks! (At least, until they
> change the formulations again...) :-)
>
>
> --
> -Jon-
>
> .- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -.
> | '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars |
> `-------------------------------- http://www.jonsteiger.com --'
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