engine MERCEDES-BENZ C-CLASS 1999 Workshop Manual

Premium Unleaded Gasoline

Caution !
To maintain the engine's durability and performance, premium unleaded gasoline must be used. If premium unleaded
is not available and low octane fuel is used, follow these precautions:
• have the fuel tank filled only partially with unleaded regular and fill up with premium unleaded 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 luggage,
• do not exceed 2/3 of maximum accelerator pedal positi on, 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 an d the Motor (M) octane number: [(R+M)/2]. This is also
known as ANTI-KNOCK INDEX. Unleaded gasoline containing oxygenates such as Ethanol, I PA, IBA and TBA can
be used provided the ratio of any one of these oxygenates to gasoline does not exceed 10%, MTBE not to exceed
15%. The ratio of Methanol to gasoline must not exceed 3% plus additional components. Using mixtures of Ethanol
and Methanol is not allowed. 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..


Gasoline Additives
A major concern among engine manufacturers is carbon build up caused by gasoline. Mercedes- Benz recommends
the use of only quality gasoline containing additives that prevent the build up of carbon deposits. After an extended
period of using fuels without such additives, carbon deposit s can build up especially on the intake valves and in the
combustion area, leading to engine performance problems such as:
• warm-up hesitation,
• unstable idle,
• knocking/pinging,
• misfire,
• power loss.
Do not blend other specific fuel additives with fuel. They only result in unnecessary cost, and may be harmful to the
engine operation. Damage or malfunctions resulting from poor fuel quality or from blending specific fuel additives are
not covered by the Mercedes-Benz Limited Warranty.


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Coolants

The engine coolant is a mixture of water and anticorrosion/antifreeze, which provides:
• corrosion protection,
• freeze protection,
• boiling protection (by increasing the boiling point).
The cooling system was filled at the factory with a coolant providing freeze protection to approx. -22°F
(-30°C) and corrosion protection. The coolant solution mu st be used year round to provide the necessary corrosion
protection and increase in the boil-over protection. You should have it replaced every 3 years. To provide the
important corrosion protection, the solution must be at leas t 45% anticorrosion/antifreeze (equals a freeze protection
to approx. -22°F [-30°C]). If you use a solution that is mo re than 55% anticorrosion/antifreeze (freeze protection to
approx. -49°F
[-45°C]), the engine temperature will increase due to the lo wer heat transfer capability of the solution. Therefore, do
not use more than this amount of anticorrosion/ant ifreeze. If the coolant level is low, water and MB
anticorrosion/antifreeze should be used to bring it up to the proper level (have cooling system checked for signs of
leakage). The water in the cooling system must meet mi nimum requirements, which are usually satisfied by normal
drinking water. If you are not sure about the water qua lity, consult your authorized Mercedes-Benz dealer.

Anticorrosion/antifreeze
Your vehicle contains a number of aluminum parts. T he use of aluminum components in motor vehicle engines
necessitates that anticorrosion/antifreeze coolant used in such engines be specifically formulated to protect the
aluminum parts. (Failure to use such anticorrosion/antifr eeze coolant will result in a significantly shortened service
life.)
Therefore the following product is strongly recommended for use in your car: Mercedes-Benz Anticorrosion/Antifreeze
Agent. Before the start of the winter season (or once a year in the hot southern regions), you should have the
anticorrosion/antifreeze concentration c hecked. The coolant is also regularly checked each time you bring your
vehicle to your authorized Merc edes-Benz dealer for service.

Model
Approx.freeze Protection
-35°F
(~37°C)

-49°F
(-45°C)


C 230 5.0 US qt
(4.75 I)

5.5 US qt
(5.25 I)

C 280 5.3 US qt
(5.0 I)

5.8 US qt
(5.5 I)

C 43 AMG 5.9US qt
(5.6 I)

6.6 US qt
(6.2 I)




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Check Regularly and Before a Long Trip

The engine compartment of model C 230 is illustrated.
1. Fuel Supply
Open flap by pushing near front (arrow). Turn fuel cap
to the left and hold on to it until possible pressure in tank
has been released, then remove cap.
Failure to remove slowly could result in personal injury.

2. Tire Inflation Pressure
Check at least every two weeks.
For details see Index.

3. Coolant Level

See Adding coolant in Index.
4. Windshield Washer System,
Headlamp Cleaning System


For refilling reservoir see Index.
5. Engine Oil Level
See Index.

6. Brake Fluid
See Index.


Vehicle Lighting: Check function and cleanliness.
For replacement of light bulbs, see Index.


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