Re: [MV] oil pressure and oil for diesel

From: Employee@MilVeh.com
Date: Sat Aug 09 2003 - 20:03:31 PDT


I have been advised never run 15-40 or 20-50 in a
diesel. You may be getting away with it, but you are
paying a hidden price according to this article:

"Multi viscosity oils are one of the great
improvements in oils, but they should be chosen
wisely. Always use a multi grade with the narrowest
span of viscosity that is appropriate for the
temperatures you are going to encounter. In the winter
base your decision on the lowest temperature you will
encounter, in the summer, the highest temperature you
expect. The polymers can shear and burn forming
deposits that can cause ring sticking and other
problems. 10W-40 and 5W-30 require a lot of
polymers(synthetics excluded) to achieve that range.
This has caused problems in diesel engines, but fewer
polymers are better for all engines. The wide
viscosity range oils, in general, are more prone to
viscosity and thermal breakdown due to the high
polymer content. It is the oil that lubricates, not
the additives. Oils that can do their job with the
fewest additives are the best.

Very few manufacturers recommend 10W-40 any more, and
some threaten to void warranties if it is used. It was
not included in this article for that reason. 20W-50
is the same 30 point spread, but because it starts
with a heavier base it requires less viscosity index
improvers (polymers) to do the job. AMSOIL can
formulate their 10W-30 and 15W-40 with no viscosity
index improvers but uses some in the 10W-40 and 5W-30.
Other multigrade synthetics may not use VI improvers
either. The full literature available from the oil
company should include this information. Follow your
manufacturer's recommendations as to which weights are
appropriate for your vehicle."

--- patrick jankowiak <eccm@swbell.net> wrote:
> Mine oil pressure holds 65 lbs at idle cold, and 50
> lbs at idle hot. I
> use 15W40, stock multifuel (fuel compensator
> bypassed) non-whistler
> turbo.
>
> I have seen pressures as low as 20 psi at idle on
> other trucks. I
> wonder what is exactly normal.
>
> Patrick
>
> "Employee@MilVeh.com" wrote:
> >
> > I can tell you what mine runs, it holds 30+ psi at
> > idle which is at 600-650 rpms with Shell's
> industrial
> > 30 wt.
> >
> > I am running stock a multi-fuel with a whistler
> turbo
> > and I love the engine. Although I was a little
> taken
> > back when a guy who owns a trucking company
> refered to
> > the engine as a "disposable" and "not worth
> > rebuilding." Sure a Cat or Cummins is a better
> > engine, but they are newer and cost a lot more
> too.
> > Considering the low price I paid for my truck,
> this
> > Continental runs like a champ and since I fixed
> the
> > fuel density compensator I have had zero problems
> with
> > it. Very happy with it and I get about 10 mpg.
> too.
> >
> > --- "Fred H. Schlesinger" <fred@schlesingers.net>
> > wrote:
> > > What is normal? Are the gauges in the truck
> pretty
> > > accurate?
> > >
> > >
> > >
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