The following steps should always be carried out in the specified order before working in the engine compartment :

Park the vehicle on a level and stable surface.

Depress and hold the brake pedal until the engine has stopped.

Apply the handbrake firmly Braking, stopping and parking Brakes Parking .

Select the neutral position or move the selector lever to P Changing gear Changing gear Automatic gearbox see Automatic gearbox_0 Automatic gearbox see Changing gear_0 Automatic gearbox Manual gearbox see Changing gear_0 Manual gearbox .

Stop the engine and remove the key from the ignition Starting and stopping the engine Engine and ignition Ignition see Engine and ignition_6 .

Allow the engine to cool sufficiently.

Children and other people should be kept well away from the engine compartment.

Ensure that the vehicle cannot roll away unexpectedly.

WARNING
Preparing the vehicle for working in the engine compartment
Opening and closing the bonnetRun-Flat Tire (PAX), Lettering On Side Wall
In contrast to conventional tires, other designations are
found on the tire flanks of PAX tires. In this way, these tires
can be allocated clearly.
PAX Tires, Designations
245  ...
General Information
All components of the refrigerant circuit submitted for
quality observation are always to be sealed (use original
sealing caps of original part).
To date, the original parts (compressor, reservoir,
receiver/dryer, evaporator and co ...
Pressures, Checking
Note
Check cooling performance. The A/C system is functioning
correctly when the air flowing from the instrument panel vents
has a temperature of 70C or lower.
Setting on Climatronic “LO”.
...