2008 MERCEDES-BENZ SL550 engine coolant

280 Operation
At the gas station
Insert fuel cap 2 into fuel filler neck
and turn fuel cap clockwise until it au-
dibly engages.
Close fuel filler flap 1.
You should hear the latch close shut.
Check regularly and before a long trip
For information on quantities and require-
ments of operating agents, see “Fuels,
coolants, lubricants, etc.” (
page 457).
Open the hood (page 282).
1Windshield washer and headlamp
cleaning system
2Brake fluid
3Coolant level
Warning!G
Overfilling of the fuel tank may create pres-
sure in the system which could cause a gas
discharge. This could cause the gas to spray
back out when removing the fuel pump noz-
zle, which could cause personal injury.
iOnly use premium unleaded gasoline with a
minimum Posted Octane Rating of 91 (average of
96 RON/86 MON).
Information on gasoline quality can normally be
found on the fuel pump. Please contact gas
station personal in case labels on the pump
cannot be found.
For more information on gasoline, see “Premium
unleaded gasoline” (
page 461), refer to the
Factory Approved Service Products pamphlet
(USA only), or contact an authorized
Mercedes-Benz-Center.
iLeaving the engine running and the fuel cap
open can cause the engine malfunction indicator
lamp ú (USA only) or the engine malfunction
indicator lamp ± (Canada only) to illuminate.
For more information, see the “Practical hints”
section (
page 346).


281 Operation
At the gas station
Windshield washer and headlamp
cleaning system
For information on refilling the reservoir,
see “Windshield washer system and
headlamp cleaning system” (
page 289).
Brake fluid
For information on brake fluid, see “Fuels,
coolants, lubricants, etc.” (
page 457).Coolant level
For information on checking the coolant
level, see “Coolant” (
page 288).
Engine oil level
For more information on checking the en-
gine oil level, see “Engine oil”
(
page 283).
Vehicle lighting
Check function and cleanliness. For more
information, see “Replacing bulbs”
(
page 409).
Exterior lamp switch, see “Switching on
headlamps” (
page 57).
Tire inflation pressure
For information on checking the tire infla-
tion pressure, see “Checking tire inflation
pressure” (
page 302).
!If you find that the brake fluid in the brake
fluid reservoir has fallen to the minimum mark or
below, have the brake system checked for brake
pad thickness and leaks immediately. Notify an
authorized Mercedes-Benz Center immediately.
Do not add brake fluid as this will not solve the
problem. For more information, see the “Practi-
cal hints” section (
page 381).

282 Operation
Engine compartment
Hood
Opening
1Hood release
Warning!G
Do not pull the release lever while the vehi-
cle is in motion. Otherwise the hood could
be forced open by passing air flow.
This could cause the hood to come loose
and injure you and/or others.
Warning!G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature gauge indicates that the engine is
overheated, do not open the hood. Move
away from the vehicle and do not open the
hood until the engine has cooled. If neces-
sary, call the fire department.
Warning!G
You could be injured when the hood is open
– even when the engine is turned off.
Parts of the engine can become very hot. To
prevent burns, let the engine cool off com-
pletely before touching any components on
the vehicle. Comply with all relevant safety
precautions.
Warning!G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running.
The radiator fan may continue to run for ap-
proximately 30 seconds or may even restart
after the engine has been turned off. Stay
clear of fan blades.
Warning!G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components (ig-
nition coils, spark plug sockets, diagnostic
socket) of the ignition system

with the engine running

while starting the engine

if ignition is “on” and the engine is
turned manually

288 Operation
Engine compartment
Coolant
The engine coolant is a mixture of water
and anticorrosion/antifreeze.
When checking the coolant level,

the vehicle must be parked on level
ground

the coolant temperature must be be-
low 158°F (70°C)The coolant expansion tank is located on
the passenger side of the engine compart-
ment.
1Coolant expansion tank
Using a rag, slowly turn the cap approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning the cap counterclock-
wise and remove it.
Warning!G
In order to avoid any potentially serious
burns:

Use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system,
or if the coolant temperature gauge indi-
cates that the coolant is overheated.

Do not remove pressure cap on coolant
reservoir if coolant temperature is
above 158°F (70°C). Allow engine to
cool down before removing cap. The
coolant reservoir contains hot fluid and
is under pressure.

Using a rag, slowly open the cap approx-
imately 1/2 turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.

Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.

289 Operation
Engine compartment
The coolant level is correct if the level

for cold coolant:
is up to the upper mark on the
bracing rib of the coolant expansion
tank (translucent)

for warm coolant:
is approximately 0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap.
For more information, see “Coolants”
(
page 463).Windshield washer system and
headlamp cleaning system
The windshield washer reservoir is located
in the engine compartment.
1Cap for windshield washer reservoir
Fluid for the windshield washer system
and the headlamp cleaning system is
supplied from the windshield washer
reservoir. It has a capacity of approxi-
mately 7.4 US qt. (7 l).
During all seasons, add MB Windshield
Washer Concentrate “MB SummerFit” to
water. Premix the windshield washer fluid
in a suitable container.
Use the tab to pull cap 1 upwards.
Refill the reservoir with MB Windshield
Washer Concentrate “MB SummerFit”
and water (or commercially available
premixed windshield washer sol-
vent/antifreeze, depending on ambient
temperatures).
For more information, see “Windshield
washer system and headlamp cleaning
system” (
page 465).
!SL 600 and SL 65 AMG: Only open the cap
on coolant expansion tank1. Never open the
cap between the two charge-air coolers. Other-
wise, the engine could be damaged.
Warning!G
Washer solvent/antifreeze is highly flamma-
ble. Do not spill washer solvent/antifreeze
on hot engine parts, because it may ignite
and burn. You could be seriously burned.
!Always use washer solvent/antifreeze
where temperatures may fall below freezing
point. Failure to do so could result in damage to
the washer system/reservoir.
!Only use washer fluid which is suitable for
plastic lenses. Improper washer fluid can dam-
age the plastic lenses of the headlamps.

348 Practical hints
What to do if …
ProblemPossible cause/consequenceSuggested solution
DThe red coolant warning lamp
comes on when the engine is
running.There is insufficient coolant in the reservoir.
If this warning lamp comes on frequently,
there is a leak in the cooling system.
If the coolant level is correct, the electric ra-
diator fan may be broken. Immediately add coolant to prevent
engine from overheating
(
page 288).
Have the cooling system checked.
If the coolant temperature is below
248°F (120°C), you can continue
driving to the nearest authorized
Mercedes-Benz Center.
Avoid high engine loads (e.g. driving
uphill) and stop-and-go driving.
DThe red coolant warning lamp
comes on when the engine is
running and you hear a warning
sound.The coolant temperature has exceeded
248°F (120°C).Stop in a safe location as soon as pos-
sible and allow the engine and coolant
to cool down.

349 Practical hints
What to do if …
During severe operating conditions, e.g.
stop-and-go traffic, the coolant tempera-
ture may rise close to 248°F (120°C).
Warning!G

Driving when your engine is overheated
can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously
burned.

Steam from an overheated engine can
cause serious burns which can occur
just by opening the hood. Stay away
from the engine if you see or hear steam
coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of
the vehicle and do not stand near the vehicle
until the engine has cooled down.
!The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious engine damage
which is not covered by the Mercedes-Benz
Limited Warranty.

383 Practical hints
What to do if …
Left displayRight displayPossible cause/consequencePossible solution
•Coolant
Stop car,

switch engine off.
The coolant is too hot.
Among other possible causes, the
poly-V-belt could be broken.Stop the vehicle in a safe location or as soon
as it is safe to do so.
Turn off the engine.
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise, the
engine will overheat due to an inoperative
water pump which may result in damage to
the engine. Contact an authorized
Mercedes-Benz Center.
If it is intact:
Wait for the message to disappear before
restarting the engine.
Doing otherwise could result in serious engine
damage that is not covered by the
Mercedes-Benz Limited Warranty.
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