Engine Oils; Brake Fluid; Premium Unleaded Gasoline; Fuel Requirements - Mercedes-Benz 300 E 1990 Owner's Manual

Engine Oils

Engine oils are specifically tested
for their suitability in our engines.
Therefore, use only engine oils
recommended by us. Information
on recommended brands is
available at your authorized
MERCEDES-BENZ dealer.

Brake Fluid

During vehicle operation, the
boiling point of the brake fluid is
continuously reduced through the
absorption of moisture from the
atmosphere. Under extremely
hard operating conditions, this
moisture content can lead to the
formation of bubbles in the sys­
tem thus reducing the system's
efficiency.
The brake fluid must therefore be
replaced annually, preferably in
the spring.
It is recommended to use only
brake fluid approved by
MERCEDES-BENZ. Your auth­
orized MERCEDES-BENZ dealer
will provide you with additional
information.
116

Premium Unleaded Gasoline

Caution!
To maintain the engine's dura­
bility and performance, premium
unleaded gasoline must be used.
If premium unleaded is not avail­
able and low octane fuel is used,
follow these precautions:
• have the fuel tank filled only
partially with unleaded regular
and fill up with premium un­
leaded as soon as possible,
• avoid full throttle driving and
abrupt acceleration,
• do not exceed an engine speed
of 3000 rpm, if the vehicle is
loaded with a light load such
as two persons and no lug­
gage,
• do not exceed 2/ 3 of maximum
accelerator pedal position, if
the vehicle is fully loaded or
operating in mountainous
terrain.

Fuel Requirements

Use only Premium unleaded
meeting ASTM standard D 439:
The octane number (posted at the
pump) must be 91 min. It is an
average of both, the Research (R)
octane number and the Motor (M)
octane number: [(R + M )/2], This
is also known as ANTI-KNOCK
INDEX.
Unleaded gasoline containing
oxygenates such as Ethanol,
MTBE, IPA, IBA and TBA can be
used provided the ratio of any one
of these oxygenates to gasoline
does not exceed 10%.
The ratio of Methanol to gasoline
must not exceed 3% plus addi­
tional cosolvents.
Using mixtures of Ethanol and
Methanol is not allowed. MTBE
may, however, be added up to
15%. Gasohol, which contains
10% Ethanol and 90% unleaded
gasoline, can be used.
These blends must also meet all
other fuel requirements such as
resistance to spark knock, boiling
range, vapor pressure, etc..