Porsche 928S 1983 Driver Manual page 38

Automatically controlled
air conditioning
The air conditioning only functions with the
engine running. The cooling effeciency is
dependent on engine revolutions. If more
cooling is required it is necessary - especial-
ly in city or stop-go conditions - to increase
engine rpm.
By automatically controlled air conditioning
the air conditioner compressor is switched on
automatically in position AUTO and Bl. The
engine runs at a higher idle speed in this po-
sition.
36
A maximum cooling effect is achieved with
the fan switch at pos. 4, the windows closed
and the side and center vents fully open.
When the air conditioner is switched on ad-
ditional cooled air is fed via a vent to the glo-
ve compartment.
If the vehicle has stood for a long time in di-
rect sunlight, it is recommended that the air
conditioning be turned on with the windows
open, to provide through ventilation.
The air conditioning must be operated for a
short period at least once a month.
This is especially important during the cold
weather when the air conditioning is not
needed.
This operation is necessary to lubricate the
expansion valve and the seals on the main-
shaft.
Should the air conditioning become defec-
tive, that is to say if warm air comes from
the inlet grills, the air conditioning must be
turned off immediately or otherwise the
cooling compressor can be damaged.