BMW X5 3.0i Owner's Manual page 164

Caring for your vehicle
164n
Exterior finish
To provide effective corrosion protec-
tion, m ultilayer paintw ork is applied
at the factory. Cataphoretic immersion
prim ing techniques are supplem ented
using special body- cavity protectants,
w ith the application of specially- devel-
oped and extensively tested m aterials.
A layer of flexible PVC is first applied to
the undercarriage. Follow ing this, a
comprehensive undercoating treat-
m ent w ith a w ax- based protectant is
applied.
Regular m aintenance m akes an impor-
tant contribution to m aintaining the
safety and value of your vehicle.
Increasing aw areness of the effects of
harm ful environm ental factors on
vehicle finishes have led paint and
vehicle m anufacturers to initiate
ongoing programs designed to further
im prove 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
determ ining the frequency and extent of
your efforts to m aintain the vehicle
finish.
Depending upon m aterial and type
of im pact (perforation of paint layer),
physical stresses from sand, road salt,
gravel, etc., can cause corrosion to
start extending beneath the finish,
starting at the point of im pact.
Road dirt, tar spots, dead insects,
anim al droppings (strong alkali effect)
and tree excretions (resins and pollen)
all contain substances capable of
causing dam age w hen allow ed to
rem ain on the finish of your vehicle for
any period of tim e (spots, etching,
flaking, separation in the top coat).
In industrial areas, deposits from fly
ash, lime, oil deposits, sulfur- dioxide in
precipitation (acid rain) and other envi-
ronmental pollutants w ill all dam age the
surface of the vehicle unless adequate
protection is provided.
In coastal regions, high levels of atm o-
spheric salt and hum idity prom ote
corrosion.
In tropical zones, tem peratures of over
+105 7 (+40 6) in the shade prevail,
in addition to heavy ultraviolet radiation
and high hum idity. Under those condi-
tions, light paints can reach tem pera-
tures up to +175 7 (+80 6) and dark
paints up to +250 7 (+120 6).
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