349 Operation
Driving instructions
Catalytic converter (gasoline engine)
Your vehicle is equipped with
monolithic-type catalytic converters, an
important element in conjunction with the
oxygen sensors to achieve substantial
control of the pollutants in the exhaust
emissions. Keep your vehicle in proper
operating condition by following our
recommended maintenance instructions
as outlined in your Maintenance Booklet.Oxidation catalyst (diesel engine)
Your vehicle is equipped with an oxidation
catalyst, an important element in conjunc-
tion with the oxygen sensors to achieve
substantial control of the pollutants in the
exhaust emissions. Keep your vehicle in
proper operating condition by following
our recommended maintenance instruc-
tions as outlined in your Maintenance
Booklet.
!To prevent damage to the catalytic convert-
ers, use only premium unleaded gasoline in this
vehicle.
Any noticeable irregularities in engine operation
should be repaired promptly. Otherwise,
excessive unburned fuel may reach the catalytic
converter, causing it to overheat and potentially
start a fire.
Warning!G
As with any vehicle, do not idle, park or op-
erate this vehicle in areas where combusti-
ble materials such as grass, hay or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.
Warning!G
As with any vehicle, do not idle, park or
operate this vehicle in areas where combus-
tible materials such as grass, hay or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.
540 Technical data
Fuels, coolants, lubricants, etc.
Fuel requirements
Gasoline engine
Only use premium unleaded fuel.
The octane number (posted at the
pump) must be 91 min. It is an
average of both the Research Octane
Number (RON) and the Motor Octane
Number (MON): (RON+MON) /2.
This is also known as the ANTI-KNOCK
INDEX.
Unleaded gasoline containing oxygenates
such as ethanol, IPA, IBA and TBA can be
used provided the ratio of any one of these
oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
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.
Diesel engine
Only use commercially available vehicular
ULTRA-LOW SULFUR HIGHWAY DIESEL
FUEL (15 ppm SULFUR MAXIMUM).
To prevent malfunctions, diesel fuel with
improved cold flow characteristics is
offered in the winter months. Check with
your fuel retailer.
Gasoline additives (gasoline engine)
A major concern among engine
manufacturers is carbon build-up caused
by gasoline. Mercedes-Benz recommends
only the use of quality gasoline containing
additives that prevent the build-up of
carbon deposits.
After an extended period of using fuels
without such additives carbon deposits
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 fill the tank with gasoline. Do not
blend diesel fuel with gasoline or kerosine.
The fuel system and engine will otherwise be
damaged, which is not covered by the
Mercedes-Benz Limited Warranty.
