BMW M5 2000, Manual, Page: 134 / 189

134 n
Caring for your car
Exterior finish
To provide effective corrosion protec-
tion, multilayer paintwork is applied at
the factory. Cataphoretic immersion
priming techniques are supplemented
using special body-cavity protectants,
with the application of specially-devel-
oped and extensively tested materials.
A layer of flexible PVC is first applied
to the undercarriage. Following this, a
comprehensive undercoating treatment
with a wax-based protectant is applied.
Regular maintenance makes an impor-
tant contribution to maintaining the
safety and value of your vehicle.
Increasing awareness of the effects of
harmful environmental factors on vehi-
cle finishes have led paint and vehicle
manufacturers to initiate ongoing pro-
grams designed to further improve the
durability of their finishes. Despite this,
environmental factors that occur locally
or regionally can have negative effects
on the finish of your vehicle. These
should guide you in determining the
frequency and extent of your efforts to
maintain the vehicle finish.
Depending upon material and type of
impact (perforation of paint layer), phys-
ical stresses from sand, road salt,
gravel, etc., can cause corrosion to start
extending beneath the finish, starting at
the point of impact.
Road dirt, tar spots, dead insects, ani-
mal droppings (strong alkali effect) and
tree excretions (resins and pollen) all
contain substances capable of causing
damage if they are allowed to remain on
the finish of your car for any period of
time (spots, etching, flaking, separation
in the top coat).
In industrial areas, deposits of flue dust,
lime, oily soot, precipitation containing
sulfur-dioxide (acid rain) and other envi-
ronmental pollutants will damage the
car's finish unless adequate care is pro-
vided – even though this is generally
limited to the outside horizontal sur-
faces.
In coastal regions, high levels of atmo-
spheric salt and humidity promote cor-
rosion.
In tropical zones, temperatures of over
105
7
(40
6
) in the shade prevail, in
addition to heavy ultraviolet radiation
and high humidity. Under those condi-
tions, light paints can reach tempera-
tures up to 175
7 (80 6 ) and dark
paints up to 250 7 (120 6 ).