Mercedes-Benz SLR McLaren. Operator's Manual.

Operation
Engine compartment
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.
The coolant expansion tank is located on
the passenger side of the engine compartment.
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 indicates
that the coolant is overheated.
Do not remove pressure cap on coolant
reservoir if coolant 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.
250
Using a rag, slowly open the cap
approximately 1 / 2 turn to relieve excess
pressure. If opened immediately, scalding
hot fluid and steam will be blown out
under pressure.
Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene
glycol which may burn if it comes into
contact with hot engine parts.
1 Expansion tank
Using a rag, turn cap slowly approximately
one half turn to the left to
release any excess pressure.
Continue turning the cap to the left and
remove it.
The coolant level is correct if the level
for cold coolant: reaches the upper
mark on the bracing rib of the expansion
tank (arrow)
for warm coolant: is approximately
0.4 in (1 cm) higher
Add coolant as required.
Replace and tighten cap.
For more information, see “Coolants”
( page 381).