I don't know it for a fact, but I think it is very plausible. As I wrote
recently, multigrade oils are not a mixture of low viscosity and high
viscosity oil -- they are a low viscosity oil with "viscosity improving"
additives, in the form of molecules which expand when heated, and combine
with the long chain molecules in the oil to "stiffen" it.
So it's very likely that an in engine with worn valve guides, for instance,
the low-viscosity base stock will be more likely to drip down the valve
guides when the engine is cold or the car is parked, causing smoking and oil
burning.
At any rate, in coastal California, where you and I live, the temperature is
extremely stable within a very narrow range, and very predictable year-
round, so choosing the appropriate single-weight oil is easy, and there is
really no reason to use a multigrade.
on 7/31/04 9:47 AM, Aeseeyou@aol.com at Aeseeyou@aol.com wrote:
> To the list;
> Am I confused (?) misinformed or "spot on" thinking that if you use a
> multi-grade or viscosity motor oil such as a 5-30 w or a 10-40w in a car with
> high
> mileage or one that is beginning to "burn oil" or emit "excessive smoke," the
> lower viscosity oils are burned off quicker or will become Smokey blow-by
> before
> the higher weight oil that came out of the can? If anyone would care to allay
> or put to rest any misconceptions about multi-grade oils that I may have
> wrongly concocted over the years I'd sure be glad to listen. But I have always
> been and will continue to remain a steadfast single grade oil person, usually
> an
> oil like a Castrol or Pennzoil 30wt. or 40wt. I also try not to mix oils, I
> try to do a complete oil drain & change using one of the above oils. If I have
> to top off or add a quart or so due to the infamous "British oil Drip" I will
> use some of the same oil that I used to change the engine oil with,
> originally.
> I will buy 2 or 3 extra quarts and keep them in the boot..just in case. I try
> to avoid buying any oil at a gas station since I feel that having to pay $3 a
> quart for just regular oil (non-synthetic) is too much to pay, even if they
> put it in themselves. (Which I try to avoid having driven away from too many
> gas stations only to smell the acrid smell of oil that has been spilled on
> the
> exhaust manifold by some klutzy (un)attendant who will never even try to clean
> off any excess spillage nor do they bother to try to tell you about the mess
> they made!
> -=Safety-Fast!=-
> Albert Escalante Owner 1978 MGB
> The Central Coast British Car Club (CA)
> Ventura, CA (info: www.ccbcc.org)
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires
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