Porsche 928 S 1984 Owner's Manual page 64

Chassis
The lower body shell of your Porsche is thor-
oughly protected against corrosion. However,
it is recommended to have the underbody in-
spected twice a year. Any detected damage to
the undercoating, due to road hazards, should
be repaired promptly. Oil based protective
sprays must not be applied. Only tar or wax
based anti-corrosion protectors are compatible
with the factory applied undercoating. Before
application, road dirt and oily substances must
be removed.
Whenever the lower body shell, axle, trans-
mission or engine assemblies are repaired,
the lost anti-corrosion coating of the af-
fected surface should be renewed.
Let your Porsche dealer advise and assist you.
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