2017 MERCEDES-BENZ GLS-Class SUV coolant temperature

Engine
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
;NThe yellow Check Engine warning lamp lights up while the engine is running.
There may be a malfunction, for example:
Rin the engine management
Rin the fuel injection system
Rin the exhaust system
Rin the ignition system (for vehicles with gasoline engines)
Rin the fuel system
The emission limit values may be exceeded and the engine may be in emergency
mode.
XVisit a qualified specialist workshop immediately.
Vehicles with a diesel engine: the fuel tank has been run dry (
Ypage 156).
XStart the engine three to four times after refueling.
If the yellow Check Engine warning lamp goes out, emergency running mode is
canceled. The vehicle need not be checked.
In some states, you must immediately visit a qualified specialist workshop as soon
as the yellow Check Engine warning lamp lights up. This is due to the legal require-
ments in effect in these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving.
8N The yellow reserve fuel warning lamp lights up while the engine is running.
The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.
8N The yellow reserve fuel warning lamp flashes while the vehicle is in motion.
In addition, the ;Check Engine warning lamp may light up.
The fuel filler cap is not closed correctly or the fuel system is leaking.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed: close the fuel filler cap.
XIf the fuel filler cap is closed:visit a qualified specialist workshop.
?NThe red coolant warning lamp lights up while the engine is running and the
coolant temperature gauge is at the start of the scale.
The temperature sensor for the coolant temperature gauge is malfunctioning.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 159).
XConsult a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster283
On-board computer and displays
Z

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
?NThe red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked or
the electric engine radiator fan may be defective.
The coolant is too hot and the engine is no longer being cooled sufficiently.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 159).
XLeave the vehicle and keep a safe distance from the vehicle until the engine has cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 322).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
XDo not start the engine again until the coolant temperature is below 248 ‡
(120 †). Otherwise, the engine could be damaged.
XDrive to the nearest qualified specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-and-go traffic.
?N The red coolant warning lamp comes on while the engine is running.
The coolant temperature has exceeded 248 ‡ (120 †). The airflow to the engine
radiator may be blocked or the coolant level may be too low.
GWARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can cause some fluids which
may have leaked into the engine compartment to catch fire.
Steam from the overheated engine can also cause serious burns which can occur
just by opening the hood.
There is a risk of injury.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 159).
XLeave the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 322).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
284Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
XAt coolant temperatures below 248 ‡ (120 †), drive to the nearest qualified
specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-and-go traffic.
Driving systems
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
·NThe red distance warning lamp lights up while the vehicle is in motion. A warning
tone also sounds.
You are approaching a vehicle, a pedestrian or a stationary obstacle in your line of travel at too high a speed.
XBe prepared to brake immediately.
XPay careful attention to the traffic situation. You may have to brake or take
evasive action.
Further information on Distance Pilot DISTRONIC (
Ypage 174).
Further information on the distance warning function of Active Brake Assist
(
Ypage 64).
Warning and indicator lamps in the instrument cluster285
On-board computer and displays
Z

Where possible, let the engine cool down andtouch only the components described in the
following.
GWARNING
The cooling system is pressurized, particularly
when the motor is warm. If you open the cap,
you could be scalded if hot coolant sprays out.
There is a risk of injury.
Let the engine cool down before you open the
cap. Wear gloves and eye protection. Slowly
open the cap to relieve pressure.
GWARNING
Windshield washer concentrate could ignite if it comes into contact with hot engine compo-
nents or the exhaust system. There is a risk of
fire and injury.
Make sure that no windshield washer con-
centrate is spilled next to the filler neck.
Checking coolant level
XPark the vehicle on a level surface.
Only check the coolant level when the vehicle
is on a level surface and the engine has cooled
down.
XTurn the SmartKey to position 2in the ignition
lock (Ypage 138).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (
Ypage 140).
XCheck the coolant temperature gauge in the
multifunction display.
The coolant temperature must be below
158 ‡ (70 †).
XTurn the SmartKey to position 0in the ignition
lock (Ypage 138).
XOn vehicles with KEYLESS-GO, press the
Start/Stop button (Ypage 140).
XPress the Start/Stop button (Ypage 140).
XSlowly turn cap :half a turn counter-clock-
wise and allow excess pressure to escape.
XTurn cap :further counter-clockwise and
remove it.
If the coolant is at the level of marker bar =
in the filler neck when cold, there is enough
coolant in coolant expansion tank ;.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar =in the filler neck
when warm, there is enough coolant in expan-
sion tank ;.
XIf necessary, add coolant that has been tested
and approved by Mercedes-Benz.
XReplace cap :and turn it clockwise as far as
it will go.
For further information on coolant, see
(
Ypage 382).
Adding washer fluid to the windshield
washer system
Example: washer fluid reservoir
XTo open: pull cap:upwards by the tab.
XAdd the premixed washer fluid.
XTo close: press cap :onto the filler neck
until it engages.
If the washer fluid level drops below the recom-
mended minimum of 1 liter, a message appears
in the multifunction display prompting you to
add washer fluid (
Ypage 273).
Further information on windshield washer fluid
(
Ypage 383).
322Engine compartment
Maintenance and care

Gasoline enginesMB-Freigabe orMB-Approval
All models229.5
Diesel enginesMB-Freigabe orMB-Approval
GLS 350 d 4MATIC228.51, 229.31,229.51, 229.52
Mercedes-AMG vehicles: only use SAE 0W-40
or SAE 5W-40 engine oils.
iMB approval is indicated on the oil contain-
ers.
Filling capacities
The following values refer to an oil change
including the oil filter.
ModelCapacity
GLS 350 d 4MATIC8.5 US qt (8.0 l)
GLS 550 4MATIC
Mercedes‑AMG
vehicles9.0 US qt (8.5l)
Allot her models7.4 US qt (7.0 l)
Additives
!Do not use any additives in the engine oil.
This could damage the engine.
Brake fluid
GWARNING
The brake fluid constantly absorbs moisture
from the air. This lowers the boiling point of
the brake fluid. If the boiling point of the brake
fluid is too low, vapor pockets may form in the
brake system when the brakes are applied
hard. This would impair braking efficiency.
There is a risk of an accident.
You should have the brake fluid renewed at
the specified intervals. Comply with the important safety notes for ser-
vice products when handling brake fluid
(
Ypage 378).
The brake fluid change intervals can be found in
the Maintenance Booklet.
Only use brake fluid approved by Mercedes-
Benz in accordance with MB-Freigabe or MB-
Approval 331.0.
Information about approved brake fluid can be
obtained at any qualified specialist workshop or on the Internet at
http://bevo.mercedes-benz.co m.
iHave the brake fluid regularly replaced at a
qualified specialist workshop in accordance
with the replacement intervals and the
replacement confirmed in the Maintenance
Booklet.
Coolant
Important safety notes
GWARNING
If antifreeze comes into contact with hot com- ponents in the engine compartment, it may
ignite. There is a risk of fire and injury.
Let the engine cool down before you add anti-
freeze. Make sure that antifreeze is not spilled
next to the filler neck. Thoroughly clean the
antifreeze from components before starting
the engine.
!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 Ser-
vice Products, MB BeVo 310.1, e.g. on the
Internet 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 cooling system is not
sufficiently protected from corrosion and
overheating.
iHave the coolant regularly replaced at a
qualified specialist workshop and the replace-
ment confirmed in the Maintenance Booklet.
382Service products and filling capacities
Technical data

Comply with the important safety notes for ser-
vice products when handlin g coolant
(
Ypage 378).
The coolant isa mixture of water and ant i-
freeze/corrosion inh ibitor. It is responsible for
the foll owing:
RAnti-corrosion protection
RAntifreeze protection
RRaisin g the boiling point
If the coolant has antifreeze protection downto
-35 ‡ (-37 †), the boilingpoin t of the coolant
during operation is approximately 266 ‡
(130 †).
The antifreeze concentrate /corrosion inh ibitor
concentration inthe engine co oling system
should:
Rbe at least 50 %.This willprotect the engine
co olin g system against freezing downto
approximate ly-35 ‡ (-37 †).
Rnot exceed 55% (antifreeze protection down
to -49 ‡ [-45 †]). Otherwise, heat willnotbe
dissipat ed as effectively.
Mercedes-Benz recommends an antifreeze/
corrosion inh ibitor concentrate inaccordance
wit h MB Specifications for Service Products
310.1.
iWhen the veh icle isfirstdeliv ered, it is fille d
wit h a coolant mixture that ensures adequate
antifreeze and anti-corrosion protection.
iThe coolant ischecked with every mainte-
nance interval at a qualified specialist work-
shop.
Filling capacities
ModelCapacity
Mercedes ‑AMG
vehiclesApprox. 11.9 US qt
(11.3 l)
GLS350d 4MAT ICApprox. 12.2 US qt
(11.5 l)
GLS550 4MATICApprox. 12.0 US qt
(11.4 l)
All other modelsApprox. 10.3 US qt
(9.7 l)
Windshield washer system
Important safety notes
GWARNING
Windshield washer concentrate could ignite if
it comes into contact with hot engine compo-
nents or the exhaust system. There isa risk of
fire and injury.
Make sure that no windshield washer con-
centrate is spilled next to the filler neck.
!Only MB SummerFit and MB WinterF it
washer fluid should bemixed together. The
spray nozzles may otherwise become
blocked.
Do not use distilled or de-ionized water. Other-
wise, the level sensor may givea false reading.
When handling washer fluid, observe the impor-
tant safety notes on service products
(
Ypage 378).
At temperatures above freezing:
XFill the washer fluid reservoir with a mixture of
water and windshield washer fluid, e.g. MB
SummerFit.
Add 1 part MB SummerFit to 100 parts water.
At temperatures below freezing:
XFill the washer fluid reservoir with a mixture of
water and washer fluid, e.g. MB WinterFit.
For the correct mixing ratio refer to the infor-
mation on the antifreeze reservoir.
iAdd windshield washer fluid, e.g. MB Sum-
merFit or MB WinterFit, to the washer fluid all
year roun d.
Climate control system refrigerant
Important safety notes
The clim ate control system of your vehicle is fil-
led with refrigerant R‑ 134a.
The instruction label regarding the refrigerant
type used can be found on the radiator cross
member.
!Only the refrigerant R‑134a and the PAG oil
approved by Mercedes-Benz may be used.
The appr oved PAG oil may not be mixed with
any other PAG oil that is not approved for
Service products and filling capacities383
Technical data
Z