2004 MERCEDES-BENZ ML350 engine overheat

222 OperationEngine compartment
Screw filler cap2 back on filler neck.
More information on engine oil can be
found in the “Technical data” section
(
page 300) and (
page 301).
Transmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Light
Truck Center check the automatic trans-
mission.Coolant
The engine coolant is a mixture of water
and anticorrosion / antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
!Excess oil must be siphoned or drained
off. It could cause damage to the
engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.
Warning!
G
In order to avoid any possibly 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 engine temperature is above
194°F (90°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 ½ 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.


249 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
/
The yellow coolant warning lamp
comes on when the engine is
running.
The coolant is to hot.
The coolant level is too low.

Stop as soon as possible and allow
the engine and coolant to cool down.

Check the coolant level and add
coolant if necessary (
page 222).
If the warning lamp comes on frequently,
there is a leak in the cooling system.

Have the cooling system checked by
an authorized Mercedes-Benz Light
Truck Center.
The coolant temperature gauge is above
248 °F (120 °C).
The coolant level is too low.

Stop as soon as possible and allow
the engine and coolant to cool down.

Add coolant to prevent engine from
overheating (
page 222).
If the coolant level is correct, the electrical
radiator fan may be broken.

If the coolant temperature is below
the red zone, drive on to the nearest
authorized Mercedes-Benz Light
Truck Center.
Avoid high engine loads (e.g. driving
uphill) and stop-and-go driving.

250 Practical hintsWhat to do if …Warning!
G
Driving when your engine is badly overheat-
ed 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 and can occur just by opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.Warning!
G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You can be seriously burned.
!Do not ignore the coolant warning
lamps. Extended driving with the sym-
bol displayed may cause serious engine
damage not covered by the
Mercedes-Benz Limited Warranty.
Do not drive without sufficient amount
of coolant. The engine will overheat,
causing major engine damage.

252 Practical hintsWhat to do if …Problem
Possible cause
Suggested solution
{
The yellow ETS malfunction indi-
cator lamp comes on while driv-
ing.
4-ETS has switched off to prevent overheat-
ing of the brakes. Also see 4-ETS / ESP warn-
ing lamp (
page 251).
As soon as the brakes have cooled off,
4-ETS switches on again.
The indicator lamp goes out.
4-ETS is malfunctioning and has switched off.

Have the 4-ETS checked at an autho-
rized Mercedes-Benz Light Truck Cen-
ter as soon as possible.
ê
The yellow LOW RANGE indicator
lamp flashes after one or more
switching conditions.
The gear selection conditions have not been
adhered to.

Repeat the gear selection process
(page 125).
ê
The yellow LOW RANGE indicator
lamp flashes after switching the
ignition on.
LOW RANGE mode is malfunctioning.
Have the LOW RANGE mode checked at
an authorized Mercedes-Benz Light Truck
Center.
The yellow fuel tank reserve
warning lamp comes on while
driving.
The fuel level has gone below the reserve
mark.

Refuel at the next gas station
(page 214).
The yellow fuel tank reserve
warning lamp flashes when leav-
ing the engine running.
The fuel cap is not closed tightly.

Check the fuel cap (
page 214).