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Examples of approved viscosity classes
Engine oils
Use only engine oils which meet the specifi-
cations
designated
by
Porsche.
Porsche dealer will be glad to advise you on
the correct type of oil for your engine.
These oils can be intermixed.
Since, however, each brand of oil has a spe-
cial composition, you should, if possible, use
the same oil brand if it becomes necessary
to top up between oil changes. Porsche en-
gines
have long
intervals
changes. You can make best use of these
long oil change intervals by using multigrade
oils or multigrade fuel efficient oils since
these are largely independent of seasonal
fluctuations in temperature.
If your vehicle is used in stop-and-go traffic
in winter, the engine will not always reach its
optimum operating temperature. Condensa-
tion from products of combustion may ac-
cumulate in the oil. It is therefore advisable
to change the oil in spring so that your en-
gine once again has an 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 en-
gine against corrosion. To perform these
functions, the oil contains additives which
LOOK
have been specially developed for these
FOR THIS
LABEL
functions. So-called mineral oils are pro-
duced directly from crude oil. The oils can
be further refined (hydrocrack) or totally con-
verted through a number of chemical pro-
Your
cesses (synthetic oils). These oils are struc-
turally more efficient and require fewer addi-
tives than simple mineral oils.
The efficiency of an oil is expressed, for
example, by the API classifications which
are divided into categories "S" and "C". The
degrees of quality are expressed by final let-
ters in alphabetical order. The requirements
between
oil
for Porsche engines are API class SE/CC to
SF/CD.
Viscosity
Engine oil is viscous when cold, and thin-
bodied when warm. The viscosity of an oil is
expressed by its SAE class. For cold viscos-
ity (measured at temperatures below 0° C)
the SAE class is 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.
The viscosity of an oil is, therefore, always
the same if it has the same number of an SAE
class.
E.g.: A 10 W-30 oil and a 10 W-40 oil have
the same viscosity when cold (below 0° C);
when 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 multi-
grade 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 have low viscosity at low
temperatures and high thermal stability at
high temperatures.
As high-performance oils, these oils are
manufactured only as synthetic or hydroc-
rack oils at present.
67
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