Engine Oils - Porsche 92854 Owner's Manual

Engine oils

Use only engine oils which meet the specifi-
cations designated by PORSCHE. Your
Porsche dealer will be glad to advise you on
the correct type of oil for your engine. All cur-
rent engine oils are compatible with each
other, i.e. when making an oil change it is not
necessary to flush the engine if you wish to
use a different brand or grade of oil. Since,
however, each brand of oil has a special com-
position, y o u should, i f possible, u s e the s a m e
oil brand if it becomes necessary to top up
between oil changes. PORSCHE engines
have long intervals between oil changes. You
can make best use of these long oil change
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intervals by using multigrade oils since these
are largely independent of seasonal fluctua-
tions in temperature.
If your vehicle is used frequently in stop-and-
go traffic in winter, the engine will not always
be properly warmed up. Condensation from
products of combustion may accumulate in
the oil. In this case, it is advisable to change
the oil in spring so that your engine once again
has a 100 % efficient engine oil.
Engine oil performance class
Engine oil is not only a lubricant, but also
serves to keep the engine clean, to neutralize
the dirt which penetrates into the engine
through combustion and to protect the engine
a g a i n s t corrosion. To perform t h e s e functions,
the oil is provided with additives which have
been specially developed for these functions.
So-called mineral oils are produced directly
from crude oil. The oils can be further refined
or totally converted through a number of chemi-
cal processes. These oils are structurally more
efficient and require fewer additives than
simple mineral oils.
The efficiency of an oil is expressed, for ex-
ample, by the API classifications which are
divided into categories "S" and "C". The de-
grees of quality are expressed by final letters
in alphabetical order. The requirements for
PORSCHE engines are API class SE/CC to
SF/CD.
Viscosity
Like all liquids, engine oil is viscous w h e n cold,
and thin-bodied when warm. The viscosity of
an oil is expressed by its SAE class. For cold
viscosity (measured at temperatures below
0° C) the SAE class given as a number and
the letter "W" (as in winter), for hot viscosity
(measured at 100° C) the SAE class is given
only as a number.
T h e viscosity o f a n oil is, therefore, a l w a y s t h e
same if it has the same number of an SAE class.
E.g.: A10 W-30 oil and a 10 W-40 oil h a v e the
s a m e viscosity when cold ( b e l o w 0 ° C); w h e n
hot (at 100° C) the oil with the number 30 is
thinner than the oil with the number 40.
Single-grade/multigrade oils
Oils with two viscosities are called multigrade
oils; oils with only one viscosity are termed
single-grade oils.
Single-grade oils can only be used for the
narrow temperature range identified by their
SAE number; multigrade oils cover a wider
temperature range (see chart).
Fuel-efficient-oils
Fuel-efficient-oils reduce internal friction in
the engine. PORSCHE approves only fuel-
efficient-oils which are structurally so stable
that they can be used in PORSCHE engines
both as summer and winter oils (see chart of
a r e a s o f application f o r oils o f different viscos-
ity). These conditions a r e currently fulfilled b y
synthetic or hydrocrack fuel-efficient-oils.