Mercedes-Benz S-Class 2019 Operator's Manual page 404

402 Maintenance and care
Park the vehicle on a level surface.
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Check the coolant temperature display in the
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instrument cluster.
The coolant temperature must be below
158 °F (70 °C).
If necessary, remove the cover.
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Slowly turn cap 1 counter-clockwise to
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relieve overpressure.
Continue turning cap 1 counter-clockwise
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and remove it.
The coolant level is correct:
If the engine is cold, up to marker bar 2.
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If the engine is warm, up to 0.6 in (1.5 cm)
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over marker bar 2.
If necessary, add coolant that has been
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approved by Mercedes-Benz.
Further information on coolant:
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( page 472)
→
Adding washer fluid to the windshield
washer system
& WARNING Risk of burns from hot com‐
ponent parts in the engine compartment
Certain component parts in the engine com‐
partment can be very hot, e.g. the engine,
the cooler and parts of the exhaust system.
Let the engine cool down and only
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touch the component parts described
as follows.
& WARNING Danger of burns when open‐
ing the hood
If you open the hood when the engine has
overheated or during a fire in the engine
compartment, you could come into contact
with hot gases or other escaping operating
fluids.
Before opening the hood, allow the
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engine to cool down.
In the event of a fire in the engine com‐
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partment, keep the hood closed and
call the fire service.
& WARNING ‑ Risk of fire and injury from
windshield washer concentrate
Windshield washer concentrate is highly
flammable. It could ignite if it comes into
contact with hot engine component parts or
the exhaust system.
Make sure that no windshield washer
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concentrate spills out next to the filler
opening.