2008 MERCEDES-BENZ GL320 check engine

529 Practical hints
Battery
!The battery is a valve-regulated lead acid
(VRLA) battery, also referred to as “fleece” bat-
tery. Such batteries do not require topping-up of
the electrolyte level. VRLA batteries therefore do
not have cell caps and the battery cover is
non-removable. Do not attempt to open the bat-
tery as otherwise the battery will be damaged.
Even though VRLA batteries do not require top-
ping-up of the electrolyte level and cannot be
opened to check the electrolyte level, the bat-
tery condition must be checked periodically by
performing a battery conductance test. Refer to
Maintenance Booklet for battery condition test-
ing intervals.
As with any other battery, the battery may dis-
charge if the vehicle is not operated for an ex-
tended period of time. You can connect a battery
maintenance charge unit tested and approved
for use on your vehicle model or disconnect the
battery to prevent battery discharge. Contact an
authorized Mercedes-Benz Light Truck Center
for more information.!The factory-equipped VRLA battery is
leak-proofed. Only use a battery as replacement
that has the same security features and is of
identical size, voltage, and capacity as the
factory-equipped battery.
The battery, the battery ventilation hose
(
page 534) and the lateral plug (page 534)
must always be securely installed when the
vehicle is in operation.
Warning!G
Jump starting must only be done using the
jump-start contacts located in the engine
compartment (
page 536).
Warning!G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and precau-
tions when handling automotive batteries
(
page 528).
Never lean over batteries while connecting,
you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.
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530 Practical hints
Battery
Disconnecting, removing, reinstalling
and reconnecting the battery
Step 1 (Disconnecting)
Set the automatic transmission to
positionP (
page 191).
Firmly depress the parking brake
(
page 67).
Turn off the engine (page 68).
Leave the ignition switched on
(
page 42).
!Never loosen or detach battery terminal
clamps while the engine is running or the
SmartKey is in the starter switch. Otherwise the
alternator and other electronic components
could be severely damaged.
Have the battery checked regularly by an
authorized Mercedes-Benz Light Truck Center.
Contact your authorized Mercedes-Benz Light
Truck Center for further information.
Warning!G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof battery only to avoid the risk
of acid burns in the event of an accident.
Warning!G
Disconnecting, removing, reinstalling and
reconnecting the battery is a complicated
and technically demanding procedure that
also requires safety precautions to avoid the
risk of injury. We strongly recommend that it
be performed by a qualified technician or an
authorized Mercedes-Benz Light Truck
Center only. Please read the instructions
fully before beginning operation and only
undertake it if you feel fully capable of
performing all of the tasks involved as de-
scribed in these instructions. Observe all
safety instructions and precautions when
handling automotive batteries
(
page 528). Performing the tasks involved
incorrectly can cause damage to the vehicle
and impair the operating safety of the
vehicle, and/or cause severe injury to you
or others.
iWith a disconnected battery you will no
longer be able to turn the SmartKey in the starter
switch and pressing the KEYLESS-GO*
start/stop button will have no effect.
iIf your battery is discharged, the vehicle
must be jump started (
page 536) using the
jump start contacts in the engine compartment,
or an accessory battery charge unit* approved
by Mercedes-Benz must be connected using the
jump start contacts in the engine compartment
(see separate instructions for the accessory bat-
tery charge unit*) before any of the following
steps can be performed. If the battery cannot be
jumped or charged, please contact an
authorized Mercedes-Benz Light Truck Center.
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536 Practical hints
Jump starting
If the battery is discharged, the engine can
be started with jumper cables and the bat-
tery of another vehicle. Observe the follow-
ing:

Jump starting should only be performed
using the jump-start contacts located
in the engine compartment
(
page 537).

Jump starting should only be performed
when the engine and catalytic
converter
1 are cold.

Do not start the engine if the battery is
frozen. Let the battery thaw out first.

Only jump start from batteries with the
same voltage rating (12 V). Jump start-
ing with a higher voltage battery could
damage the vehicle’s electrical system,
which will not be covered by the
Mercedes-Benz Limited Warranty.

Only use jumper cables with sufficient
cross-section and insulated terminal
clamps.

Always make sure the jumper cables
are not on or near pulleys, fans or other
parts that move when the engine is
started or running.
Warning!G
Failure to follow these directions will cause
damage to the electronic components, and
can lead to a battery explosion and severe
injury or death.
Never lean over batteries while connecting
or jump starting, you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water, and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and very explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking, etc.
Attempting to jump start a frozen battery
can result in it exploding, causing personal
injury.
Read all instructions before proceeding.
1Vehicles with gasoline engine only.
!Do not tow-start the vehicle.
!Avoid repeated and lengthy starting
attempts.
Do not attempt to start the engine using a
battery quick charge unit.
If the engine does not run after several unsuc-
cessful starting attempts, have it checked at the
nearest authorized Mercedes-Benz Light Truck
Center.
Excessive unburned fuel generated by repeated
failed starting attempts may damage the catalyt-
ic converter
1.
Make sure the jumper cables do not have loose
or missing insulation.
Make sure the cable clamps do not touch any
other metal part while the other end is still at-
tached to a battery.
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537 Practical hints
Jump starting
The jump-start contacts are located in the
engine compartment.
1Negative (-) terminal
2Positive (+) terminal
3Positive terminal cover
Make sure the two vehicles do not
touch.
Turn off all electrical consumers.
Apply parking brake (page 67).
Set automatic transmission to
positionP (
page 191).
Open the hood (page 378).
Remove cover from negative
terminal1.
Flip up cover3 of positive terminal2
in direction of arrow.
1Negative terminal of discharged
battery
2Positive terminal of discharged battery
4Positive terminal of charged battery
5Negative terminal of charged battery
Connect positive terminal2 and4
with the jumper cable. Clamp cable to
charged battery4 first.
Start engine of the vehicle with the
charged battery and run at idle speed.
Connect negative terminals1 and5
of the batteries with the second jumper
cable. Clamp the cable to negative
terminal5 of the charged battery
first.
Start the engine of the disabled vehi-
cle.
You can now turn on the electrical consum-
ers. Do not switch on the headlamps under
any circumstances.
Remove the jumper cables first from
negative terminals1 and5 and then
from positive terminals2 and4.
You can now switch on the headlamps.
Have the battery checked at the near-
est authorized Mercedes-Benz Light
Truck Center.
Warning!G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(
page 528).
!Never invert the terminal connections!
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544 Practical hints
Fuses
Fuse box in engine compartment
The fuse box is located on the passenger
side of the engine compartment.
Open the hood (page 378).
Fuse box GL 450 (GL 320 CDI, GL 550
similar)
1Fuse box cover
2Clamps
Pull clamps2 in direction of arrow.
Lift fuse box cover1 up.
Install fuse box cover in reverse order.
Close the hood after checking or re-
placing fuses (
page 379).
Fuse box in cargo compartment
The fuse box is located in the cargo com-
partment behind the passenger side trim
panel.
1Lock
2CoverRemoving/installing cover
Open the tailgate (page 122).
Insert a suitable object such as a coin
into the slot of lock1 (
page 544).
Turn lock1 counterclockwise by 90°
in direction of arrow.
Remove cover2.
Install cover2 in reverse order.
!The fuse box cover must be installed
properly to prevent moisture and/or dirt from
entering the fuse box and possibly impairing fuse
operation.
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566 Technical data
Fuels, coolants, lubricants
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 of-
fered 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 lossIn areas where carbon deposits may be
encountered due to lack of availability of
gasolines which contain these additives,
Mercedes-Benz recommends the use of
additives approved by us for use on
Mercedes-Benz vehicles. Refer to the
Factory Approved Service Products
pamphlet (USA only) or contact an
authorized Mercedes-Benz Light Truck
Center for a listing of approved product(s).
Follow directions on product label.
Do not blend other fuel additives with fuel.
This only results in unnecessary costs and
may be harmful to the engine operation.
!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.
!Damage or malfunction resulting from poor
fuel quality or from blending additional fuel
additives other than those tested and approved
by us for use on Mercedes-Benz vehicles are not
covered by the Mercedes-Benz Limited
Warranty.
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567 Technical data
Fuels, coolants, lubricants
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 approximately -35°F (-37°C) and corro-
sion protection.If the antifreeze mixture is effective to
-35°F (-37°C), the boiling point of the cool-
ant in the pressurized cooling system is
reached at approximately 266°F (130°C).
The coolant solution must be used year
round to provide the necessary corrosion
protection and increase boil-over protec-
tion. Refer to Maintenance Booklet for
replacement interval.
Coolant system design and coolant used
determine the replacement interval. The
replacement interval published in the
Maintenance booklet is only applicable if
MB 325.0 Anticorrosion/Antifreeze solu-
tion or other Mercedes-Benz approved
products of equal specification are used to
renew the coolant concentration or bring it
back up to the proper level.
For information on other Mercedes-Benz
approved products of equal specification,
refer to the Factory Approved Service
Products pamphlet (USA only) or contact
an authorized Mercedes-Benz Light Truck
Center.To provide important corrosion protection,
the solution must be at least 50% anticor-
rosion/antifreeze (equivalent to freeze
protection to approximately -35°F
[-37°C]). If you use a solution that is more
than 55% anticorrosion/antifreeze (freeze
protection to approximately -49°F
[-45°C]), the engine temperature will
increase due to the lower heat transfer
capability of the solution. Therefore, do not
use more than this amount of anticorro-
sion/antifreeze.
If the coolant level is low, water and
MB 325.0 Anticorrosion/Antifreeze
should be used to bring it up to the proper
level (have cooling system checked for
signs of leakage). Please make sure the
mixture is in accordance with label instruc-
tions.
The water in the cooling system must meet
minimum requirements, which are usually
satisfied by normal drinking water. If you
are not sure about the water quality, con-
sult an authorized Mercedes-Benz Light
Truck Center.
!Add premixed coolant solution only. Adding
water and MB 325.0 Anticorrosion/Antifreeze
separately from each other, could cause engine
damage not covered by the
Mercedes-Benz Limited Warranty.
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568 Technical data
Fuels, coolants, lubricants
Anticorrosion/antifreeze
Your vehicle contains a number of
aluminum parts. The 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/antifreeze coolant will result
in a significantly shortened service life.
Therefore, the following product is strongly
recommended for use in your vehicle:
MB 325.0 Anticorrosion/Antifreeze agent.Before the start of the winter season (or
once a year in hot southern regions), you
should have the anticorrosion/antifreeze
concentration checked. The coolant is also
regularly checked each time you bring your
vehicle to an authorized Mercedes-Benz
Light Truck Center for service.
Anticorrosion/antifreeze quantity
Approximate freeze protection
Model-35°F (-37°C)-49°F (-45°C)
GL 320 CDI5.0 US qt (4.75 l)5.5 US qt (5.2 l)
GL 4505.3 US qt (5.0 l)5.8 US qt (5.5 l)
GL 5501
1Data preliminary.
5.6 US qt (5.25 l)6.1 US qt (5.8 l)
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