1998 BMW CONVERTIBLE engine

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

10 0
To ensure that your vehicle provides
maximum economy throughout a long
service life, we request that you
observe the following.
Engine and differentialUp to 1,250 miles (2,000 km):
Drive at different engine speeds and
vehicle speeds, but be careful not to
exceed the following engine speed:
4,500 rpm
Refrain from using full throttle and avoid
pressing the accelerator beyond the
kickdown point.
After 1,250 miles (2,000 km) you can
gradually increase the number of revo-
lutions or the speed.
You should also observe these break-in
procedures if the engine or differential
is replaced later in the course of the
vehicle service life.
TiresDue to technical factors associated with
their manufacture, tires do not achieve
their full traction potential until an initial
break-in period has elapsed. This
means that you should drive with addi-
tional caution for the first 200 miles
(300 km).Brake systemBrake pads and disks attain their opti-
mal wear patterns only after approx.
300 miles (500 km).
EngineDo not allow the engine to warm to its
normal operating temperature by leav-
ing it idling with the vehicle parked.
However, when starting in extremely
cold weather it is a good idea to allow
the engine to run at fast idle for about
30 seconds before getting underway;
this precaution ensures adequate lubri-
cation.
Avoid high engine speeds while the
engine is still cold; this helps avoid pre-
mature wear and reduced service life.
When driving under high engine loads
(acceleration, steep hills), try to keep
the engine running above 1,500 rpm.
We recommend downshifting into a
more suitable range, especially when
driving up extended inclines.
It is a good idea to follow extended
periods of low-speed operation (dense
urban traffic, stop-and-go driving) by
maintaining an engine speed consis-
tently above 3,000 rpm for several
miles. This procedure helps prevent
deposits from accumulating in the
engine.
Break-in procedures Driving notes

101
At a glanceControlsCar careRepairsTechnicalDataIndex
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

10 2
The catalytic converter reduces harmful
exhaust emissions.
It is designed for use with unleaded fuel
only.
Even minute quantities of lead would be
enough to permanently damage both
the catalytic converter and the system's
oxygen sensor.
To ensure efficient, trouble-free engine
operation and avoid potential damage:
dAlways have your car serviced in
accordance with maintenance
instructions.
dNever continue driving until the fuel
tank is empty.
dRespond to engine miss by switching
off the engine at once.
dNever tow-start the car unless the
engine is cold, or else unburned fuel
may reach the catalytic converter.
Better yet: use jumper cables!
dAvoid other situations in which the
fuel would not be (completely)
burned, for instance:
Frequent, extended, or repeated
starting attempts during which the
engine fails to start. (Switching off
and restarting a healthy engine
causes no damage).
Never let the engine run with any of
the spark-plug cables disconnected.
a
Always observe the above points
to prevent unburned mixture from
entering the catalytic converter. This
could result in overheating, leading to
serious damage.
High temperatures occur on all vehicles
equipped with a catalytic converter.
Heat shields are installed adjacent to
some sections of the exhaust system.
Never remove these shields; do not
apply undercoating to their surfaces.
When driving, standing at idle or park-
ing the vehicle, take care to avoid con-
tact between the exhaust system and
flammable materials (e.g., grass, hay,
leaves, etc.). Such contact could lead to
a fire, resulting in personal injury and
property damage.c
Traveling abroadAlways make sure that unleaded fuel
meeting your engineÕs octane require-
ments will be available when planning
trips outside the country. The use of
fuel failing to meet the official octane
requirements could result in engine
damage.
If you are considering traveling to a
country in which unleaded fuel is not
readily available, please remember that
leaded fuel will destroy the lambda oxy-
gen sensor and the catalytic converter
on your BMW. After operation on
leaded fuel, your vehicle will no longer
meet American and Canadian exhaust
emission standards, and there will also
be a loss of fuel economy. Upon your
return to the US or Canada, you will be
expected to comply with legal ordi-
nances requiring that you replace both
the oxygen sensor and the catalytic
converter, and to have the fuel system
flushed to remove any traces of leaded
fuel.
Catalytic converter

10 3
At a glanceControlsCar careRepairsTechnicalDataIndex
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)

10 4
Disc brakes furnish optimum decelera-
tion and braking control as well as
greater fade resistance under heavy
use.
Limited vehicle use, extended periods
with the car parked or in storage and
light loading will increase the tendency
for corrosion to form on the rotors, and
dirt to accumulate on the pads. This
happens because the minimum pres-
sure between the pad and the disc
required for the self-cleaning function
of the disc brakes is not achieved.
If the brake rotors are corroded, they
will tend to respond to braking with a
pulsating effect which even extended
application will fail to cure.
a
Use only original BMW-approved
brake pads, as otherwise vehicle autho-
rization is no longer valid.c
Driving notes While driving in wet conditions and in
heavy rain, it is a good idea to apply
light pressure to the brake pedal every
few miles - Watch traffic conditions to
ensure that this maneuver does not
endanger other road users. The heat
generated in this braking process helps
dry the brake pads and rotors.
Maximum braking force is obtained
while the wheels continue to rotate,
peaking when the wheels remain on the
verge of locking without actually doing
so. ABS maintains this state automati-
cally. If the ABS fails, you should revert
to the staggered braking technique
described above (refer to page 106).
Extended or steep mountain descents
do not necessarily have to lead to
reduced braking efficiency; downshift
to a gear in which only minimal periodic
brake applications are required (you
can move the selector lever to the
appropriate lower range if your car is
equipped with an automatic transmis-
sion).
You can further increase the engine's
braking effect by selecting a lower gear,
downshifting as far as first gear or plac-
ing the selector lever in position 1 (2).Should engine braking prove inade-
quate, you should still avoid extended,
continuous braking. Instead of main-
taining low to moderate pressure over
an extended period of time, you should
decelerate the vehicle by applying more
substantial force at the pedal (watch for
following traffic!) and then pausing
before repeating the application. This
staggered braking technique allows the
brakes to cool in the intervals between
active braking phases, preventing over-
heating and ensuring that full braking
capacity remains available at all times.
a
Do not allow the vehicle to coast by
pressing down the clutch pedal or shift-
ing into neutral while underway. Never
drive with the engine switched
off (!). The engine provides no braking
effect when the clutch is disengaged or
the transmission is in neutral, and there
is no power-assist for brakes and steer-
ing when the engine is not running.
Never allow floor mats, carpets or other
objects to protrude into the area around
the accelerator, clutch and brake pedals
and obstruct their movement.c
Disc brakes

10 5
At a glanceControlsCar careRepairsTechnicalDataIndex
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

10 6
BrakesWinter road conditions substantially
reduce the amount of traction available
between the tires and the road surface;
the resulting - considerable - increases
in braking distance should be continu-
ally borne in mind.
ABS is intended to prevent the wheels
from locking under braking; to help the
vehicle to remain stable and sensitive to
steering. Should the ABS fail, with lock-
ing wheels as a result: Reduce the
pressure on the brake pedal until the
wheels just start to roll again while still
maintaining enough force to continue
braking. Then increase the pressure,
release the pressure when the wheels
lock, reapply pressure, etc.
This staggered braking procedure will
reduce stopping distances while help-
ing you maintain steering control.
It can allow you to steer around hazards
once you have reduced the pressure on
the brake pedal.
a
Never downshift to exploit engine
braking when driving on slippery road
surfaces; it could lead to loss of rear-
wheel traction and endanger vehicle
control. ABS and ASC+T can not protect
against such loss of traction, since they
have no effect on this kind of decelera-
tion.c
b
Disengage the clutch during hard
braking on road surfaces affording only
poor or uneven traction.c
Loss of lateral traction (sliding)Release the accelerator pedal and
depress the clutch pedal or push the
selector lever to position N with auto-
matic transmission. Countersteer care-
fully and attempt to regain control of the
vehicle.
ParkingSelect 1st or reverse gear. If your car is
equipped with an automatic transmis-
sion, select Park. Engage the parking
brake when parking on hills and
inclined surfaces. To prevent frost and
corrosion from locking the parking
brake liners at the drum, you can dry
them by gently pulling up the lever
while stopping (ensure that you do not
endanger following traffic).a
The brake lamps do not light up
when the parking brake is applied.c
Winter driving