BMW M3 2001 Manual page 129

Caring for your vehicle
Exterior finish
To provide effective corrosion protec-
tion, multilayer paintwork is applied at
the factory. Cataphoretic immersion
priming techniques are supplemented
with special body-cavity protectants, by
applying specially developed and
extensively tested materials.
A layer of flexible PVC is first applied to
the undercarriage. Following this, a
comprehensive undercoating treat-
ment with a wax-based protectant is
applied. Regular maintenance makes
an important contribution to maintaining
the safety and value of your vehicle.
Increasing awareness of the effects of
harmful environmental factors on
vehicle finishes have led paint and
vehicle manufacturers to initiate
programs designed to further improve
the durability of their finishes. Despite
this, regional environmental factors can
have negative effects on your vehicle's
finish. These should guide you in deter-
mining the frequency and extent of your
efforts to maintain the vehicle finish.
Depending upon material and type of
impact (perforation of paint layer),
physical stresses from sand, road salt,
gravel etc., can cause corrosion to
extend beneath the finish, starting at
the point of impact.
Road dirt, tar spots, dead insects,
animal droppings (strong alkali effect)
and tree excretions (resins and pollen)
all contain substances capable of
causing damage when allowed to
remain on the finish of your vehicle
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
environmental pollutants will damage
the vehicle's finish unless adequate
care is provided – even though this
is generally limited to the outside hori-
zontal surfaces.
In coastal regions, high levels of
atmospheric salt and humidity promote
corrosion.
In tropical zones, high humidity and
heavy ultraviolet radiation prevail, in
addition to temperatures of over 105 7
(+40 6) in the shade. Under these
conditions, light paints can reach tem-
peratures up to 175 7 (+80 6) and
dark ones up to 250 7 (+120 6).
Caring for the vehicle finish
Regular washing is a preventive
measure against long-term effects from
substances that are harmful to the
vehicle's finish, especially if you drive
your vehicle in areas with high levels
of air pollution or aggressive natural
substances (tree resins, pollen).
Nevertheless, you should immediately
remove especially aggressive
substances. Failure to do so can lead to
changes in the paint's chemical
structure or to discoloration. Gasoline
spilled during refueling, oil, grease and
brake fluid should always be cleaned
away immediately, as should bird
droppings (finish damage).
Any contamination remaining on the
surface of the vehicle will be especially
conspicuous after washing. Use
cleaning fluid or alcohol with a clean
cloth or cotton pad to remove. Remove
tar spots with tar remover. After
cleaning, the affected areas should be
waxed to ensure continued protection.
Use the cleaning and car-care
products that you can obtain at
your BMW center.<
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