Porsche 911 Carrera Owner's Manual page 260

After washing, rinse the car with plenty of
water and then dry with a chamois leather. Do
not use the same chamois leather for drying
as you use for cleaning the windshield and
windows.
Warning!
Moisture which gets on to the brakes during
a car wash can reduce braking efciency or
make the brakes pull unevenly which could
increase the danger of an accident, causing
serious personal injuries or death.
Always apply the brakes a few times after
washing the car to test braking efficiency and
dry the brake discs. When doing this, take
care not to hamper other road users behind
you (traffic conditions permitting).
Automatic car washes
Please observe the chapter "WIPER BLADES"
on page 255.
Optional add-on parts or parts which project
beyond the contours of the vehicle may be
damaged by design features (e.g. brushes) of
automatic car washes.
258
Maintenance, Car Care
The following parts are particularly susceptible
to damage:
– Convertible top (hot wax treatment cannot be
used, as the wax attacks the convertible top
material)
– Windshield wipers (always switch them off
to prevent them wiping unintentionally in
intermittent or sensor operation)
– External antennas (always unscrew)
– Roof Transport System (always remove
completely)
– Rear spoiler
– Wheels (the wider the rim and the lower the tire
height, the greater the risk of damage)
– High-gloss wheels (to prevent these from
getting scratched, do not clean with the
wheel-cleaning brushes of the car wash).
Please consult the operator before using
automatic car washes.
Wash and dry by hand all points not reached
by a car wash, such as door and lid seams or
door sills.
Note
Automatic car washes spray water at odd angles
and high pressures, which are not seen in normal
driving. Therefore, water can sometimes find its
way into the passengers compartment during or
shortly after the car wash.
Convertible top
Care and treatment
Never remove snow and ice using a sharp
edged object.
Incorrect care and treatment can damage the
convertible top and cause leaks. Any repair work
can be done by your authorized Porsche dealer.
Note
No folding top is 100% leak proof.
Due to the constant changing of loads and strains
to which a car is subject to when driving on roads,
minor wind noise and seepage at joints between
the top, body and doors on convertible tops
cannot be completely sealed in certain areas.
Therefore small leaks are considered normal
for these models. In addition, your convertible
top should not be washed in a car wash. The
top may experience damage by the brushes or
may experience leaks due to the high pressure
water streams directed in areas which would not
encounter water in normal driving conditions.