technical data BMW CONVERTIBLE 1998 Service Manual

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1 Air ßow directed against windshield
and door windows
2 Air ßow toward upper body
The rotary dial on the right affords
continuous opening or closing of the
air supply, the lever changes the
direction of the air ßow. The rotary dial
on the left tempers the air coming out
(page 92).
3 Front footwell ventilation
Corresponding vent outlets are also
located in the rear footwell.
4 ControlsAutomatic climate control

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To defrost windshield and door
windows
Air conditioner Circulated air mode/Automatic
recirculated air control (AUC)
*
Press the button repeatedly to run
through the following control sequence:
dIndicator lamps off: outside air flow
operational.
dLeft-hand indicator lamp on Ð AUC
mode: the system detects pollutants
in the outside air and responds by
deactivating the outside air flow as
required. The system then recircu-
lates the air currently within the vehi-
cle.
dRight-hand indicator lamp on: the
flow of outside air into the vehicle is
permanently blocked. The system
then recirculates the air currently
within the vehicle.a
If the windshields fog over in circu-
lated air mode, switch off the circulated
air mode/Automatic recirculated air
control and increase the air supply. if
necessary.c
Rear window defrosterBMW Convertible: Heated rear-window
blower.
The rear-window blower is always
switched off with the convertible top
down.
When the hardtop
* is in place, press
the rear-window heating button.
Temperature
This program is designed for
rapid removal of ice and con-
densation from the windshield and side
windows.
The air conditioner cools and
dehumidifies incoming air
before reheating it to the selected tem-
perature.
Depending on the weather, the wind-
shield may fog over briefly when the
engine is started.
Switching off the air conditioner at out-
side temperatures below approx. 41 5F
(56) will prevent the windows from
fogging up.
Frequently switching the air condi-
tioner on and off may also promote the
formation of condensation on the win-
dow surfaces.
b
Condensation forms in the air
conditioner system during operation,
which then exits under the vehicle. It is
not unusual for a small puddle to form
there.c
You can respond to unpleas-
ant odors in the outside air
by temporarily excluding the outside air.
The system then recirculates the air
currently within the vehicle.
A
The indicator lamp comes
on to confirm that the rear
defroster is operating.
The defroster switches off automatically
after approx. 15 minutes.
On both the driver's and the
passenger's side you can
adjust the specific temperature. The fig-
ures in the display provide a general
indication of interior temperature. We
recommend 70 5F (226) as a standard
setting for comfortable travel, both with
and without the air conditioner. When
you start the vehicle, the system
ensures that the selected temperature
is achieved as quickly as possible and
maintained at a constant level by the
control.
Automatic climate control

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BMW Hi-Fi System (Harman/
Kardon)1On
2Off
In the "On" position, the listener is given
the impression of a considerably larger
passenger compartment with an
improved stereo effect in all seats.
This function should be switched off in
the case of poor radio reception due to
the frequent changes between stereo
and mono which result.
BMW Convertible:
You do not have to operate the con-
trols. The system detects whether the
top is open or closed and regulates the
sound automatically.
To openPress the button and fold down the
door.
The glove compartment lamp switches
on from ignition key position 1.To closeFold up door.To engage locksOnly possible with a master key. a
To reduce the risk of injury, always
close the glove compartment immedi-
ately after use.c
Rechargeable flashlightThe connection for the rechargeable
flashlight is located on the left side of
the glove compartment.
The flashlight features overcharging
protection, so it can be left in its holder
continuously.
However, it must be removed when the
battery is disconnected or removed.a
Ensure that the flashlight is off be-
fore inserting it in its holder.c
HIFI
1
2
360de057
360de058
BMW Hi-Fi System*Glove compartment

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Pull the strap to fold down the armrest.
To open drawer
*:
Unlock and pull out the drawer by pull-
ing on the drawer handle. The drawer
locks in any position. The cup holder
can be shifted as necessary.
BMW ConvertibleVehicles without ski bag
*: Storage
compartment, accessible by removing
the filler piece and releasing the trim
(refer to page 97).
The rear backrest is divided in the cen-
ter. Each side can be folded down sep-
arately to carry long objects.
To release:
Reach into the handle recess, press
down and pull forward.
When folding back the rear backrest,
make sure that the locking device is
properly engaged to ensure proper
operation of the safety belt. The red
slide must move downward.
If the rear backrest is not locked, the
safety belt can not be pulled out.It makes possible a safe, convenient
transport of 3 to a maximum of 4 pairs
of skis (BMW Convertible, maximum of
2 pairs of skis).
The length of the ski bag in combination
with the additional space in the luggage
compartment makes it possible to trans-
port skis of up to 6.8 ft. (2.10 m) in
length. Because the ski bag contracts
as additional skis are inserted, the bag
is suitable for transporting only two
pairs of skis when both are a maximum
of 6.8 ft. (2.10 m) long.
If the ski bag is not used for longer peri-
ods, it should be stored in a dry place.
It is advisable to wipe off any water
which has collected on the waterproof
ski bag from time to time.
a
The ski bag must not hinder the
driver during driving.c
360de027
BMW Sedan/ Cou
pe
Center armrest (rear)*Through-loading system*Ski bag*

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BMW Convertible - loading the ski
bagRemoving filler piece.Detach cut-out trim at bottom.
Extend the ski sack between the front
seats. The zipper provides convenient
access to the inside of the sack, and
can also be left open to promote drying.
b
When remounting the trim, press it
firmly onto the guide rod at the bot-
tom.cOpen the cover panel from the luggage
compartment and use the magnetic
retainers to attach it to the lower side of
the rear shelf within the luggage com-
partment.
b
Secure the stored skis or other
objects by tightening down the strap on
the ski bag at the buckle.c
For general information on the ski bag,
refer to page 95.
36cde003
36cde004
36cde005
Ski bag*

At a glance
Controls and featuresCare and maintenanceAdvanced technology
Technical data
Owner service procedure
At a glanceControlsCar careRepairsTechnicalDataIndex
Index
99
Special operating instructions:
Break-in procedures100
Driving notes100
Catalytic converter102
Antilock Brake System (ABS)103
Disc brakes104
Brake system105
Winter driving105
Roof-mounted luggage rack107
Radio reception108
Cellular phones108
Hardtop Ð Convertible109
Technical modifications to
the vehicle110
Wheels and tires:
Tire inflation pressures111
Tire tread111
Tire replacement112
Interaxle tire changes112
The right choice113
Winter tires114
Approved wheels and tires115Under the hood:
Hood118
Engine compartment 120
Washer fluids124
Engine oil124
Coolant127
Brake fluid128
Power steering fluid128
Vehicle Identification Number118
Care and maintenance:
The BMW Maintenance
System130
Caring for your car131
Cleaning and care of the
convertible top136
Vehicle storage137

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ClutchDepress the clutch throughout its com-
plete travel range to shift gears. Do not
"ride" the clutch by driving with your
foot resting against the pedal.a
Brakes:
Do not drive with your foot resting on the
brake pedal. Even light but consistent
pedal pressure can lead to high temper-
atures, brake wear and possibly even
brake failure.
Aquaplaning:
A wedge of water can form between
tires and road surface when you oper-
ate the vehicle on wet or slushy roads.
This phenomenon is referred to as
aquaplaning, or hydroplaning, and it is
characterized by a partial or complete
loss of contact between the tires and
the road surface. The ultimate results
are loss of steering and braking control.Water on the roads:
When driving through water (maximum
depth one foot = 30 cm) always drive at
walking speed, otherwise damage to
the engine, the electrical system and
the transmission can occur.
Rear window shelf:
Never use the rear window shelf to
store heavy or bulky objects. They
could pose a danger to the occupants
when the car is braked heavily.
Clothes hooks:
When suspending clothing from the
hooks, ensure that they will not obstruct
the driver's vision. Refrain from hanging
heavy objects from the hooks, as these
could cause personal injury when the
car is braked heavily.c
Driving notes

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ABS enhances active safety by helping
to prevent the wheels from locking under
braking. When the front wheels slide, the
driver loses steering control over the
vehicle. Traction loss at the rear wheels
can cause the rear end to break into
uncontrolled oversteer.
ABS is designed to meet two essential
requirements during every application:
dto help provide vehicle stability on all
types of road surface (asphalt,
cement, dirt, moisture, snow and ice).
dto help to retain steering and maneu-
vering capability under the same con-
ditions.
However, certain important consider-
ations must be borne in mind in connec-
tion with these requirements:
Not even ABS can suspend the normal
laws of physics. ABS alone can not pre-
vent accidents when the brakes are
applied without an adequate safety
interval between vehicles, when the car
reaches excessive rates of lateral accel-
eration in curves, or if aquaplaning
occurs. Responsibility for these types of
situations remains in the hands (and feet)
of the driver. You should never allow the
added safety of ABS to lull you into a
false sense of security, or mislead you
into taking increased risks that could
affect your own safety and that of others.
Driving with ABSThe yellow ABS warning in the instru-
ment panel goes out as soon as the
engine is started.
The system becomes operative once the
vehicle exceeds a speed of 5 mph
(8 km/h). The ABS is deactivated when-
ever the vehicle's speed drops below
approx. 2 mph (3 km/h). This means that
the wheels can lock in the Þnal phase of
a braking action - a factor of no signiÞ-
cance in actual practice.
The ABS system closed-loop control cir-
cuit cycles in fractions of a second. A
pulsation at the brake pedal indicates to
the driver that ABS is active, that is, that
the car is within its maximum braking
range. In addition, the audible pulsation
that accompanies the control operation
calls your attention to the reduced trac-
tion between tires and road surface
(marginal adhesion), and reminds you
that the vehicle's speed should be
reduced to adapt to road conditions.On road surfaces featuring a loose top
layer on a Þrmer substratum, e.g., on
gravel or snow, the braking distances
with ABS may be longer than with the
wheels locked. However, ABS continues
to provide enhanced vehicle and steer-
ing control under these conditions.
a
To ensure that the system remains
completely operational, never modify the
ABS. Service procedures on ABS are to
be performed by authorized technicians
only.c
ABS may fail to function with maximum
efÞciency when tires of different sizes
are mounted (e.g., winter tires/spare tire;
remount the correct tires at all wheels as
soon as possible).
In the event of a fault, the ABS warning
lamp in the instrument cluster lights up,
refer to page 18. The braking system
then reverts to conventional operation as
on a vehicle without ABS. However,
have the brake system checked by your
BMW Retailer as soon as possible. To
prevent undetected defects and cumu-
lative faults from adversely affecting the
brake system, refer any problems to
your authorized BMW Retailer at the
earliest opportunity.
Antilock Brake System (ABS)

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Failure of one brake circuitPedal travel increases, more pressure is
required at the pedal.
The remaining circuit continues to pro-
vide good braking response.a
In the event of any malfunction in
the brake system, consult the nearest
BMW Retailer as soon as possible.cThe onset of winter is often accompa-
nied by rapid changes in weather.
Adaptations in driving style should be
accompanied by preparations on the
vehicle itself to ensure that your
progress through the winter remains
safe and trouble-free.
CoolantEnsure that the coolant contains the
year-round 50:50 ratio of water and
antifreeze with corrosion inhibitor. This
mixture provides protection against
freezing down to approximately -345F
(-376). Replace the coolant every
three years.Lockscan be made operative again using
BMW lock de-icer. This de-icer also
contains lubricants.
In addition, a treatment with BMW lock
cylinder grease is recommended.Rubber seals and components To prevent the weather-stripping from
freezing, apply a spray-on rubber treat-
ment or silicone spray to the door, hood
and luggage compartment lid seals.b
A complete range of car-care
products is available from any autho-
rized BMW Retailer.c
Snow chainsBMW snow chains
* can be mounted on
both summer and winter tires. Mount
them in pairs on the rear wheels only
and observe the manufacturer's safety
precautions. Do not exceed a maximum
speed of 30 mph (50 km/h). For maxi-
mum traction, deactivate ASC+T when
driving with snow chains mounted, refer
to page 84.
Starting offWhen driving off in deep snow or "rock-
ing" the vehicle to free it, you should
switch off ASC+T, refer to page 84. Driving on low-traction road
surfacesOperate the accelerator pedal sensi-
tively, avoid high engine speeds and
shift up to the next-higher gear early.
Shift down into the next lowest gear
when approaching uphill or downhill
grades. Maintain an adequate distance
between yourself and the car ahead.
Brake system Winter driving

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A special luggage system is available as
an option for your BMW. Please
observe the precautions included with
the installation instructions.
Because roof racks raise the center of
gravity of the car when loaded, they
exercise a major effect on its handling
and steering response.
You should therefore always remember
not to exceed the approved roof weight,
the approved gross vehicle weight or
the axle weights when loading the rack.
For specifications refer to "Technical
data", page 163ff.
Make sure that the load is not too heavy,
and attempt to distribute it evenly.
Always load the heaviest items first (on
the bottom).
Make sure there is sufficient space to
raise the sliding/tilt sunroof.Secure the roof luggage correctly and
securely to prevent it from shifting or
being lost during driving (danger to fol-
lowing traffic).
Drive smoothly: avoid sudden accelera-
tion and braking maneuvers; corner
gently.
The roof load increases the surface
area exposed to the wind: increased
fuel consumption and stress on the roof
are the immediate results.Roof-mounted luggage rack*