
If only regular unleaded petrol with an
octane rating of 91 RON/82.5 MON or
loweri s available, you must have the vehi-
cle adapted to this fuel at a qualified spe-
cialist workshop.
i E10 fuel contains up to 10% bioethanol.
Your vehicle is E10-compatible. You can
refuel your vehicle using E10 fuel.
SLK 350 BlueEFFICIENCY
! Only refuel using premium-grade sulphur-
free unleaded petrol with at least 95 RON/
85 MON that conforms to European stand-
ard EN 228 or an equivalent specification.
You could otherwise impair engine output
or damage the emission control system.
i In some countries, the available petrol
may not be sufficiently low in sulphur. This
fuel can temporarily produce unpleasant
odours, especially on short journeys. As
soon as sulphur-free fuel (sulphur content
<10p pm) is used for refuelling, the odours
are reduced.
Additives
! Do not refuel with low grade fuel and do
not use fuel additives that have not been
tested and approved for Mercedes-Benz
vehicles. Otherwise the fuel system could
malfunction or be damaged.
One of the major problems with low-grade
fuel is the creation of carbon deposits during
the process of burning fuel. Mercedes-Benz
recommends that you use fuel brands that
have additives.
If you use fuels without these additives for a
longer period of time, there may be a build-up
of carbon deposits. These will form especially
on the inlet valves and in the combustion
chamber.
This could lead to engine running problems,
e.g.:
R longer engine warm-up phase
R uneven idle
R engine noise R
misfiring
R loss of power
In areas where petrol with the required addi-
tives is not available, carbon deposits can
build up. In this case, Mercedes-Benz recom-
mends the use of additives that have been
approved for Mercedes-Benz vehicles; see
http://bevo.mercedes-benz.com.
Consult a Mercedes-Benz Service Centre to
view a list of approved products. Observe the
instructions for use in the product descrip-
tion.
Do not mix other fuel additives with fuel. This
causes unnecessary costs and could damage
the engine.
Diesel (EN 590) Fuel grade
G
WARNING
Do not use petrol to refuel vehicles with a die-
sel engine. Do not mix diesel with petrol. This
would result in damage to the fuel system and
engine, which could lead to a vehicle fire.
! When refuelling, only use diesel fuel that
conform stothe European standard EN 590
or is of equivalent quality. Fuel that does
not conform to EN 590 can lead to
increased wear as well as damage to the
engine and exhaust system.
! Do not use the following:
R marine diesel
R heating oil
R bio-diesel
R vegetable oil
R petrol
R paraffin
R kerosene
Do not mix these fuels with diesel fuels and
do not use any special additives. Other-
wise, this can lead to damage to the engine.
This excludes flow improver; see "Low out-
side temperatures". Service products and capacities
305Technical data Z 

!
Vehicles with adiesel particle filter: in
countries outside the EU, only refuel with
low-sulphur Euro diesel with a sulphur con-
ten tunde r50p pm; otherwise the emission
control system could be damaged.
! Vehicles without adiesel particle fil-
ter: in countries where only diesel fuel with
a high sulphur conten tis available, you will
need to carry out your vehicle's oil change
at shorter intervals. More information
aboutt he interval for oil change can be
obtained from any qualified specialist
workshop.
Usually you will find information about the
fuel grade on the pump. If you cannot find the
label on the petrol pump, ask the filling sta-
tion staff.
Information on refuelling (Y page 142).
Low outside temperatures
In winter months, diesel fuel with an improved
cold flow quality is available. In Europe, the
EN 590 standard defines various climate-
dependent temperature categories. Malfunc-
tions can be avoided by refuelling with diesel
fuel that corresponds to the climatic specifi-
cations outlined in EN 590. At unusually low
outside temperatures, it is possible that the
flow characteristics of the diesel fuel could be
insufficient .Accordingly, diesel fuel from
warmer areas may not be suitable for opera-
tion in colder climati cconditions.
i Further information on country-specific
fuel properties can be obtained from oil
companies, e.g. at filling stations.
Flow improver
To improve the low-temperature resistance of
diesel fuel, a flow improver can be attached.
The effectiveness of a flow improver is not
guaranteed for every fuel.
Only use flow improvers tested and approved
by Mercedes-Benz. During use, please
observe the information on operation.
Correct dosage and sufficient mixing are deci-
sive in improving low-temperature resistance with the flow improver. Overdosage can
potentially even decrease low-temperature
resistance and must therefore be avoided.
Follow the manufacturer's guidelines on dos-
age.
Mix the additive into the diesel in good time,
before the flow characteristics of the diesel
become insufficient. Otherwise, malfunctions
can arise through heating the fuel system,
e.g. through parking in a heated garage.
More information about recommended flow
improvers can be obtained from any qualified
specialist workshop.
Notes on fuel consumption
H
Environmental note
CO 2(carbon dioxide) is the gas which scien-
tists believe to be principally responsible for
global warming (the greenhouse effect). Your
vehicle's CO 2emissions are directly related to
fuel consumption and therefore depend on:
R efficient use of the fuel by the engine
R driving style
R other non-technical factors, such as envi-
ronmental influences or road conditions
You can minimise your vehicle's CO 2emis-
sions by driving carefully and having it serv-
iced regularly.
The vehicle will use more fuel than usual in
the following situations:
R at very low outside temperatures
R in urban traffic
R on short journeys
R in mountainous terrain
i Only for certain countries: you can find
the current consumption and emission val-
ues of your vehicle in the COC documents
(EU CERTIFICATE OF CONFORMITY). These
documents are delivered with your vehicle.
The consumption figures were in each case
based on the currently applicable version: 306
Service products and capacitiesTechnical data 

Additives
!
Do no tuse any additives with the engine
oil. This could damage the engine.
Engine oil viscosity Viscosity describes the flow characteristics
of a fluid. If an engine oil has a high viscosity
rating, it flows slowly; the lower the viscosity,
the faster it flows.
Engine oil selection is based on the respective
outside temperatures and in accordance with
the SAE classification (viscosity). The table
shows you which SAE classifications are to be
used. The low-temperature properties of
engine oils can be significantly impaired dur-
ing operation due to, for example, ageing or
soot and fuel accretion. It is therefore
strongly recommended to observe regularo
il
changes using an approved engine oil with the
appropriate SA Eclassification. Brake fluid
G
WARNING
Over a period of time, the brake fluid absorbs
moisture fro mthe air; This lowers its boiling
point.
If the boiling point of the brake fluid is too low,
vapour pockets may form in the brake system
when the brakes are applied hard (e.g. when
driving downhill). This impairs braking effi-
ciency. You should have the brake fluid renewed at
regular intervals. The brake fluid change inter-
vals can be found in the Service Booklet.
Only use brake fluid approved by Mercedes-
Benz.I nformation abou tapproved brake fluid
can be obtained at any qualified specialist
workshop or on the Internet at
http://bevo.mercedes-benz.com.
i Have the brake fluid regularly checked at
a qualified specialist workshop.
There is usually a notice in the engine com-
partment to remind you when the next
brake fluid change is due. Coolant
Important safety notes G
WARNING
Antifreeze is highly flammable. Fire, naked
flames and smoking are prohibited when han-
dling antifreeze.
If antifreeze comes into contact with hot
engine parts, it may ignite and you could burn
yourself. Do not spill any antifreeze on hot
engine parts.
! Only add coolant that has been premixed
with the desired antifreeze protection. You
could otherwise damage the engine.
Further information on coolants can be
found in the Mercedes-Benz Specifications
for Service Products, MB Specifications for
Service Products 310.1, e.g. on the Inter-
net at http://bevo.mercedes-benz.com.
Or contact a qualified specialist workshop.
! Always use a suitable coolant mixture,
even in countries where high temperatures
prevail.
Otherwise, the engine coolin gsystem is not
sufficiently protected from corrosion and
overheating.
! The engine cooling system is filled with
coolant, which mus tbe renewed after 308
Service products and capacitiesTechnical data