maintenance reset BMW 3 SERIES 1986 E30 Workshop Manual

1
Engine
Oil filter
M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C121
M20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C160
M30 engines
3-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C160
5-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X115
M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X120
Valve clearances (intake and exhaust)
M10 engines
Cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 mm
Hot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 mm
M20 engines
Cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 mm
Hot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 mm
M30 engines
Cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 mm
Hot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.35 mm
M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydraulic adjusters
Cooling system
Antifreeze mixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40% antifreeze/60% water
Chapter 1
Routine maintenance and servicing
Air filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Automatic transmission fluid and filter change . . . . . . . . . . . . . . . . . 28
Automatic transmission fluid level check . . . . . . . . . . . . . . . . . . . . . 8
Battery check, maintenance and charging . . . . . . . . . . . . . . . . . . . . 13
Brake system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Cooling system - draining, flushing and refilling . . . . . . . . . . . . . . . . 29
Cooling system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Differential lubricant change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Differential lubricant level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Driveshaft gaiter check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Drivebelt check, adjustment and renewal . . . . . . . . . . . . . . . . . . . . . 11
Engine idle speed and CO level check and adjustment . . . . . . . . . . 12
Engine oil and filter change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Engine timing belt renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Evaporative Emissions Control (EVAP) system check . . . . . . . . . . . 33
Fluid level checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Fuel system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Manual transmission lubricant change . . . . . . . . . . . . . . . . . . . . . . . 31
Manual transmission lubricant level check . . . . . . . . . . . . . . . . . . . . 16
Power steering fluid level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Routine maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Service light resetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Spark plug check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Spark plug HT leads, distributor cap and rotor - check
and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Steering and suspension check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Throttle linkage - check and lubrication . . . . . . . . . . . . . . . . . . . . . . 19
Tyre and tyre pressure checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Tyre rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Tune-up general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Underbonnet hoses - check and renewal . . . . . . . . . . . . . . . . . . . . . 10
Valve clearances - check and adjustment . . . . . . . . . . . . . . . . . . . . 18
Wiper blades - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1•1
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty
Specifications Contents

Maintenance schedule
The following maintenance intervals are based on the assumption
that the vehicle owner will be doing the maintenance or service work,
as opposed to having a dealer service department do the work.
Although the time/mileage intervals are loosely based on factory rec-
ommendations, most have been shortened to ensure, for example, that
such items as lubricants and fluids are checked/changed at intervals
that promote maximum engine/driveline service life. Also, subject to
the preference of the individual owner interested in keeping his or her
vehicle in peak condition at all times, and with the vehicle’s ultimate
resale in mind, many of the maintenance procedures may be
performed more often than recommended in the following schedule.
We encourage such owner initiative.
When the vehicle is new, it should be serviced initially by a factory-
authorised dealer service department, to protect the factory warranty.
In many cases, the initial maintenance check is done at no cost to the
owner (check with your dealer service department for more
information).
1•4Maintenance and servicing
Every 250 miles or weekly, whichever
comes first
m mCheck the engine oil level (Section 4)
m mCheck the engine coolant level (Section 4)
m mCheck the brake fluid level (Section 4)
m mCheck the clutch fluid level (Section 4)
m mCheck the washer fluid level (Section 4)
m mCheck the tyres and tyre pressures (Section 5)
Every 6000 miles or 6 months,
whichever comes first
All items listed above, plus:
m mChange the engine oil and oil filter (Section 6)
m mCheck the power steering fluid level (Section 7)
m mCheck the tyres, and rotate if necessary (Section 9)
m mCheck the automatic transmission fluid level
(Section 8)
m mCheck the underbonnet hoses (Section 10)
m mCheck/adjust the drivebelts (Section 11)
m mCheck engine idle speed and CO (Section 12)
Every 12 000 miles or 12 months,
whichever comes first
All items listed above, plus:
m mCheck/service the battery (Section 13)
m mCheck the spark plugs (Section 14)
m mCheck/renew the HT leads, distributor cap and
rotor (Section 15)
m mCheck/top-up the manual transmission lubricant
(Section 16)
m mCheck the differential oil level (Section 17)
m mCheck the valve clearances, and adjust if
necessary - does not apply to M40 engines
(Section 18)
m mCheck and lubricate the throttle linkage (Section 19)
m mRenew the air filter (Section 20)
m mCheck the fuel system (Section 21)
m mInspect the cooling system (Section 22)
m mInspect the exhaust system (Section 23)
m mInspect the steering and suspension components
(Section 24)
m mCheck the driveshaft gaiter(s) (Section 25)
m mInspect the brakes (Section 26)
m mInspect/renew the windscreen wiper blades
(Section 27)
Every 24 000 miles or 2 years,
whichever comes first
All items listed above plus:
m mChange the automatic transmission fluid and filter
(Section 28)
m mDrain, flush and refill the cooling system (Section 29)
m mRenew the spark plugs (Section 14)
m mCheck/renew the spark plug HT leads (Section 15)
m mRenew the fuel filter (Section 30)
m mChange the manual transmission lubricant (Section 31)
m mChange the differential oil (Section 32)
m mCheck the evaporative emissions system, where
applicable (Section 33)
m mReset the service indicator lights (Section 34)
m mRenew brake fluid by bleeding (see Chapter 9)
m mCheck the handbrake operation (see Chapter 9)
Every 60 000 miles
m
mRenew the timing belt (Section 35)

1•5
Underbonnet view (left-hand side) of a
UK model 318i (1988)
1 Radiator
2 Intake manifold
3 Idle control valve
4 Accelerator cable
5 Diagnostic/service indicator resetting
socket
6 Fuse/relay box
7 Brake hydraulic fluid reservoir
8 Airflow meter
9 Air cleaner unit
10 Radiator filler cap
11 Radiator top hose
12 Oil filter housing
Underbonnet view (right-hand side) of a
UK model 318i (1988)
1 Oil filler cap
2 Valve cover
3 Engine oil filler dipstick
4 Viscous cooling fan
5 Distributor cap cover
6 Bottom hose
7 Windscreen washer fluid reservoir
8 Ignition coil
9 Clutch hydraulic fluid reservoir
10 Battery
1
Maintenance and Servicing

13 Battery check, maintenance
and charging
2
Check and maintenance
Warning: Certain precautions
must be followed when checking
and servicing the battery.
Hydrogen gas, which is highly
flammable, is always present in the battery
cells, so keep lighted tobacco and all other
flames and sparks away from it. The
electrolyte inside the battery is actually
dilute sulphuric acid, which will cause
injury if splashed on your skin or in youreyes. It will also ruin clothes and painted
surfaces. When disconnecting the battery
cables, always detach the negative cable
first, and connect it last!
1Battery maintenance is an important
procedure, which will help ensure that you are
not stranded because of a dead battery.
Several tools are required for this procedure
(see illustration).
2Before servicing the battery, always switch
off the engine and all accessories, and
disconnect the cable from the negative
terminal of the battery.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code before
disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
3A low-maintenance battery is standard
equipment. The cell caps can be removed and
distilled water can be added, if necessary.
Later models may be fitted with a
“maintenance-free” battery, which is sealed.
4Remove the caps and check the electrolyte
level in each of the battery cells. It must be
above the plates. There’s usually a split-ring
indicator in each cell to indicate the correct
level. If the level is low, add distilled water
only, then refit the cell caps.Caution: Overfilling the cells may
cause electrolyte to spill over
during periods of heavy charging,
causing corrosion and damage to
nearby components.
5If the positive terminal and cable clamp on
your vehicle’s battery is equipped with a
rubber protector, make sure that it’s not torn
or damaged. It should completely cover the
terminal.
6The external condition of the battery should
be checked periodically. Look for damage
such as a cracked case.
7Check the tightness of the battery cable
clamps to ensure good electrical connections.
Check the entire length of each cable, looking
for cracked or abraded insulation and frayed
conductors.
8If corrosion (visible as white, fluffy deposits)
is evident, remove the cables from the
terminals, clean them with a battery brush,
and reconnect them (see illustrations).
Corrosion can be kept to a minimum by fitting
specially treated washers available at car
accessory shops, or by applying a layer of
petroleum jelly or suitable grease to the
Every 12 000 miles or 12 months, whichever comes first
1•16
13.8d When cleaning the cable clamps, all
corrosion must be removed (the inside of
the clamp is tapered to match the taper on
the post, so don’t remove too much
material)
13.8c Regardless of the type of tool used
on the battery posts, a clean, shiny surface
should be the result
13.1 Tools and materials required for
battery maintenance
1 Face shield/safety goggles- When
removing corrosion with a brush, the acidic
particles can easily fly up into your eyes
2 Baking soda - A solution of baking soda and
water can be used to neutralise corrosion
3 Petroleum jelly- A layer of this on the
battery posts will help prevent corrosion
4 Battery post/cable cleaner- This wire-
brush cleaning tool will remove all traces of
corrosion from the battery posts and cable
clamps
5 Treated felt washers- Placing one of
these on each post, directly under the
cable clamps, will help prevent corrosion
6 Puller- Sometimes the cable clamps are
very difficult to pull off the posts, even after
the nut/bolt has been completely loosened.
This tool pulls the clamp straight up and off
the post without damage
7 Battery post/cable cleaner - Here is
another cleaning tool which is a slightly
different version of No 4 above, but it does
the same thing
8 Rubber gloves- Another safety item to
consider when servicing the battery;
remember that’s acid inside the battery!
13.8b Removing a cable from the battery
post with a spanner - sometimes special
battery pliers are required for this
procedure, if corrosion has caused
deterioration of the nut (always remove the
earth cable first, and connect it last!)
13.8a Battery terminal corrosion usually
appears as light, fluffy powder
Every 12 000 miles

terminals and cable clamps after they are
assembled.
9Make sure that the battery carrier is in good
condition, and that the hold-down clamp bolt
is tight. If the battery is removed (see Chap-
ter 5 for the removal and refitting procedure),
make sure that no parts remain in the bottom
of the carrier when it’s refitted. When refitting
the hold-down clamp, don’t overtighten the
bolt.
10Corrosion on the carrier, battery case and
surrounding areas can be removed with a
solution of water and baking soda. Apply the
mixture with a small brush, let it work, then
rinse it off with plenty of clean water.
11Any metal parts of the vehicle damaged
by corrosion should be coated with a zinc-
based primer, then painted.
12Additional information on the battery and
jump starting can be found in Chapter 5 and
the front of this manual.
Charging
Note: The manufacturer recommends the
battery be removed from the vehicle for
charging, because the gas which escapes
during this procedure can damage the paint or
interior, depending on the location of the
battery. Fast charging with the battery cables
connected can result in damage to the
electrical system.
13Remove all of the cell caps (if applicable),
and cover the holes with a clean cloth to
prevent spattering electrolyte. Disconnect thebattery negative cable, and connect the
battery charger leads to the battery posts
(positive to positive, negative to negative),
then plug in the charger. Make sure it is set at
12 volts if it has a selector switch.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery. Note: If,
after connecting the battery, the wrong
language appears on the instrument panel
display, refer to page 0-7 for the language
resetting procedure.
14If you’re using a charger with a rate higher
than two amps, check the battery regularly
during charging to make sure it doesn’t
overheat. If you’re using a trickle charger, you
can safely let the battery charge overnight
after you’ve checked it regularly for the first
couple of hours. Where a maintenance-free
battery is fitted, special precautions may be
necessary when charging it (for example, the
charge rate is normally very low). There may
be a warning label on the battery, but if not,
consult a BMW dealer or auto-electrician.
15If the battery has removable cell caps,
measure the specific gravity with a
hydrometer every hour during the last few
hours of the charging cycle. Hydrometers are
available inexpensively from car accessory
shops - follow the instructions that come with
the hydrometer. Consider the battery charged
when there’s no change in the specific gravity
reading for two hours, and the electrolyte in
the cells is gassing (bubbling) freely. The
specific gravity reading from each cell should
be very close to the others. If not, the battery
probably has a bad cell(s), and a new one
should be fitted.
16Some maintenance-free (sealed) batteries
have built-in hydrometers on the top,
indicating the state of charge by the colour
displayed in the hydrometer window.
Normally, a bright-coloured hydrometer
indicates a full charge, and a dark hydrometer
indicates the battery still needs charging.
Check the battery manufacturer’s instructions
to be sure you know what the colours mean.17If the battery is sealed and has no built-in
hydrometer, you can connect a digital
voltmeter across the battery terminals to
check the charge. A fully-charged battery
should read 12.6 volts or higher.
18Further information on the battery and
jump starting can be found in Chapter 5 and
at the front of this manual.
14 Spark plug check and
renewal
1
1Before beginning, obtain the necessary
tools, which will include a spark plug socket
and a set of feeler blades. Special spark plug
gap gauges can be obtained from certain
spark plug manufacturers (see illustration).
2The best procedure to follow when
renewing the spark plugs is to purchase the
new spark plugs beforehand, adjust them to
the proper gap, and then renew each plug one
at a time. When buying the new spark plugs, it
is important to obtain the correct plugs for
your specific engine. This information can be
found in the Specifications section in the front
of this Chapter.
3With the new spark plugs at hand, allow the
engine to cool completely before attempting
plug removal. During this time, each of the
new spark plugs can be inspected for defects
and the gaps can be checked.
4The gap is checked by inserting the proper
thickness gauge between the electrodes at the
tip of the plug (see illustration). The gap
between the electrodes should be the same as
that given in the Specifications. The wire
should just touch each of the electrodes. If the
gap is incorrect, use the notched adjuster to
bend the curved side of the electrode slightly
until the proper gap is achieved (see
illustration). Note: When adjusting the gap of a
new plug, bend only the base of the earth
electrode, do not touch the tip. If the earth
electrode is not exactly over the centre
electrode, use the notched adjuster to align the
two. Check for cracks in the porcelain insulator,
indicating the spark plug should not be used.
1•17
14.4b To change the gap, bend the earth
electrode only, as indicated by the arrows,
and be very careful not to crack or chip the
porcelain insulator surrounding the centre
electrode14.4a Spark plug manufacturers
recommend using a wire-type gauge when
checking the gap - if the wire does not
slide between the electrodes with a slight
drag, adjustment is required
14.1 Tools required for changing spark
plugs
1 Spark plug socket- This will have special
padding inside to protect the spark plug’s
porcelain insulator
2 Torque wrench - Although not mandatory,
using this tool is the best way to ensure the
plugs are tightened properly
3 Ratchet - Standard hand tool to fit the
spark plug socket
4 Extension - Depending on model and
accessories, you may need special
extensions and universal joints to reach one
or more of the plugs
5 Spark plug gap gauge- This gauge for
checking the gap comes in a variety of
styles. Make sure the gap for your engine is
included. Feeler blades may be used
instead
1
Every 12 000 miles

the lubricant will be hot, it would be wise to
wear rubber gloves.
3Raise the vehicle and place it on axle
stands. Make sure it is safely supported, and
as level as possible.
4Move the necessary equipment under the
vehicle, being careful not to touch any of the
hot exhaust components.
5Place the drain pan under the transmission,
and remove the filler/level plug from the side
of the transmission. Loosen the drain plug
(see illustration).
6Carefully remove the drain plug. Be careful
not to burn yourself on the lubricant.
7Allow the lubricant to drain completely.
Clean the drain plug thoroughly, then refit and
tighten it securely.
8Refer to Section 16 and fill the transmission
with new lubricant, then refit the filler/level
plug, tightening it securely.
9Lower the vehicle. Check for leaks at the
drain plug after the first few miles of driving.
32 Differential lubricant change
1
1Drive the vehicle for several miles to warm
up the differential lubricant, then raise the
vehicle and support it securely on axle stands.
2Move a drain pan, rags, newspapers and an
Allen key under the vehicle. Since the
lubricant will be hot, wear rubber gloves to
prevent burns.
3Remove the filler/level plug from the
differential; this is the upper of the two plugs.
4With the drain pan under the differential,
loosen the drain plug; this is the lower of the
two plugs (see illustration).
5Carefully unscrew the drain plug until you
can remove it from the case.
6Allow all the oil to drain into the pan, then
refit the drain plug and tighten it securely.
7Refer to Section 17 and fill the differential
with lubricant.
8Refit the filler/level plug and tighten it
securely.
9Lower the vehicle. Check for leaks at the
drain plug after the first few miles of driving.
33 Evaporative emissions
control (EVAP) system check
1
1The function of the evaporative emissions
control system is to draw fuel vapours from
the tank and fuel system, store them in a
charcoal canister, and then burn them during
normal engine operation. This system is
normally only fitted to those vehicles
equipped with a catalytic converter.
2The most common symptom of a fault in
the evaporative emissions system is a strong
fuel odour in the engine compartment. If a fuel
odour is detected, inspect the charcoal
canister and system hoses for cracks. The
canister is located in the front corner of the
engine compartment on most models (see
illustration).
3Refer to Chapter 6 for more information on
the evaporative emissions system.
34 Service indicator light
resetting
4
Service indicator lights
1All models covered in this manual are
equipped with various service indicator lights
on the facia, which automatically go on when
the mileage interval is reached. These lights
can only be turned off by using a special tool
which plugs into the service connector
located in the engine compartment.
2Although the service light resetting tool can
be obtained from a dealer, reasonably-priced
alternatives may also be available from
aftermarket sources. When obtaining a tool, it
is important to know the vehicle year and
model, and whether the service connector has
15 or 20 pins (see illustrations). Once the
proper tool is obtained, it is a simple matter to
plug it into the service connector and,
following the tool manufacturer’s instructions,
reset the service lights. Note: The brake
warning light will not automatically reset if the
sensor on the brake pad (or its wiring) isdamaged because it is worn through: it must
be repaired first.
3The service lights are controlled by the
Service Indicator (SI) board in the instrument
cluster, which is powered by rechargeable
batteries. Should these batteries fail,
problems will develop in the SI board.
Symptoms of failed batteries include the
inability to reset the service lights and
malfunctions affecting the tachometer,
temperature gauge and radio operation. Refer
to Chapter 12 for more information on the SI
board.
Every 60 000 miles
35 Engine timing belt renewal
5
Note:This is not included in the
manufacturer’s maintenance schedule, but is
strongly recommended as a precaution
against the timing belt failing in service. If the
timing belt fails while the engine is running,
extensive engine damage could be caused.
Refer to Chapter 2A, Section 10.
1•26
34.2b An aftermarket service light
resetting tool such as this one can be
plugged into the service connector and
used to reset the service lights
34.2a The earlier 15-pin connector
(arrowed) is mounted near the front of the
engine. The 20-pin connector used on later
models is located in the left rear corner of
the engine compartment33.2 Inspect the hoses (arrowed) at the
top of the evaporative emissions charcoal
canister for damage32.4 Remove the differential drain plug
with an Allen key
Every 24 000 miles

12Disconnect the cables from the clips
securing them to the lever assembly, marking
them for accurate refitting.
13Disconnect the electrical connection from
the control assembly.
14Remove the screws attaching the bezel to
the control assembly, and remove the control
assembly.
Refitting
15Refitting is the reverse of the removal
procedure.
11 Heater matrix-
removal and refitting
1
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
1Disconnect the battery negative cable.
2Drain the cooling system (see Chapter 1).
3Remove the centre console (see Chap-
ter 11). Spread an old blanket over the front
carpeting; this will prevent stains if any
residual coolant spills.
Removal
3-Series models
4Remove the left-hand side heater ducting,
and set it aside.
5Remove the heater valve clamp.
6Remove the screws and detach the flange
where the two coolant lines enter the heater
matrix case. Be careful; some coolant may
spill.
7Remove the two screws holding the heater
matrix case to the heater main assembly.
8Slide the heater matrix out of the mounting.
Be careful not to spill any of the remaining
coolant in the heater matrix when removing it.
5-Series models
9Disconnect the temperature sensor
electrical connectors.
10Disconnect the straps holding the wiring
to the case, and set the wiring out of the way.
11Unfasten the cover fasteners.
12Remove the screws holding the cover in
place, then remove the cover.
13Disconnect all heater pipe connections
attached to the heater matrix. Be careful;
some coolant may spill.
14Lifting on the right side of the heater
matrix first, remove the heater matrix.
Refitting
Note: Always use new O-rings when attaching
the coolant lines to the heater matrix.15Refitting is the reverse of removal. Refill
the cooling system (see Chapter 1), then run
the engine with the heater on, and check for
correct operation and leaks.
12 Air conditioning system-
precautions and maintenance
1
Precautions
Warning: The air conditioning
system is under high pressure.
DO NOT loosen any hose or line
fittings, or remove any
components, until after the system has
been discharged. Air conditioning
refrigerant should be properly discharged
by a qualified refrigeration engineer. The
refrigerant used in the system must not be
allowed into contact with your skin or
eyes, or there is a risk of frostbite. Should
the refrigerant come into contact with a
naked flame, a poisonous gas will be
produced. Smoking in the presence of
refrigerant is therefore highly dangerous,
particularly if refrigerant vapour is inhaled
through a lighted cigarette. The refrigerant
is heavier than air, and it may cause
suffocation if discharged in an enclosed
space such as a domestic garage.
Finally, uncontrolled release of the
refrigerant causes environmental damage,
by contributing to the “greenhouse
effect”.
Maintenance
1The following maintenance checks should
be performed on a regular basis to ensure the
air conditioner continues to operate at peak
efficiency:
a) Check the drivebelt. If it’s worn or
deteriorated, renew it (see Chapter 1).
b) Check the system hoses. Look for cracks,
bubbles, hard spots and deterioration.
Inspect the hoses and all fittings for oil
bubbles and seepage. If there’s any
evidence of wear, damage or leaks, have
new hose(s) fitted.
c) Inspect the condenser fins for leaves, flies
and other debris. Use a “fin comb” or
compressed air to clean the condenser.
d) Make sure the system has the correct
refrigerant charge, as described below.
2It’s a good idea to operate the system for
about 10 minutes at least once a month,
particularly during the winter. Long-term non-
use can cause hardening, and subsequent
failure, of the seals.
3Because of the complexity of the air
conditioning system and the special
equipment necessary to service it, in-depth
fault diagnosis and repair procedures are not
included in this manual. However, simple
checks and component renewal procedures
are provided in this Chapter.
4The most common cause of poor cooling issimply a low system refrigerant charge. If a
noticeable loss of cool air output occurs, the
following quick check may help you determine
if the refrigerant level is low.
5Warm the engine up to normal operating
temperature.
6Set the air conditioning temperature
selector at the coldest setting, and put the
blower at the highest setting. Open the doors
(to make sure the air conditioning system
doesn’t switch off as soon as it cools the
passenger compartment).
7With the compressor engaged - the
compressor clutch will make an audible click,
and the centre of the clutch will rotate - feel
the tube located adjacent to the right front
frame rail, near the radiator.
8If a significant temperature drop is noticed,
the refrigerant level is probably OK.
9If the inlet line has frost accumulation, or
feels cooler than the receiver-drier surface,
the refrigerant charge is low. Recharging the
system should be carried out by a qualified
refrigeration engineer.
13 Air conditioning compressor
- removal and refitting
5
Warning: Due to the potential
dangers associated with the
system, you are strongly advised
to have any work on the air
conditioning system carried out by a BMW
dealer or air conditioning specialist. At the
very least, DO NOT dismantle any part of
the system (hoses, compressor, line
fittings, etc.) until after the system has
been discharged by a qualified engineer.
Refer to the precautions given at the start
of Section 12.
Note: If a new compressor is fitted, the
receiver-drier (see Section 16) should also be
renewed.
Removal
1Have the air conditioning system
discharged (see Warning above).
2Disconnect the battery negative cable.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
3Disconnect the compressor clutch wiring
harness.
4Remove the drivebelt (see Chapter 1).
5Disconnect the refrigerant lines from the
rear of the compressor. Plug the open fittings
to prevent entry of dirt and moisture.
6Unbolt the compressor from the mounting
3•8 Cooling, heating and air conditioning systems

Withdraw the sensor from its bracket and
remove it.
11When fitting the new sensor, use a brass
feeler gauge to position the tip of the sensor
the correct distance from the pulse wheel
(see illustration).
12Tighten the mounting bolt, but be careful
not to overtighten it.
13 Charging system- general
information and precautions
There are two different types of alternator
fitted on these models; Bosch and Motorola.
Also, there are three different amperage
ratings available; 65A, 80A or 90A. A stamped
serial number on the rear of the alternator will
identify the type and amperage rating.
Perform the charging system checks (see
Section 14) to diagnose any problems with the
alternator.
The voltage regulator and the alternator
brushes are mounted as a single assembly.
On Bosch alternators, this unit can be
removed from the alternator (see Section 16)
and the components serviced individually.
The alternator on all models is mounted on
the left front of the engine, and utilises a V-
belt and pulley drive system. Drivebelt tension
and battery servicing are the two primary
maintenance requirements for these systems.
See Chapter 1 for the procedures regarding
engine drivebelt checking and battery
servicing.
The ignition/no-charge warning light should
come on when the ignition key is turned to
Start, then go off immediately the engine
starts. If it remains on, there is a malfunction
in the charging system (see Section 14). Some
vehicles are also equipped with a voltmeter. If
the voltmeter indicates abnormally high or low
voltage, check the charging system (see
Section 14). Note:On models up to 1986, a
blown ignition/no-charge warning light will
prevent the alternator from charging. After
1987, a resistor is wired in parallel with the
warning light in order to allow current tobypass the light in the event of a broken circuit
(blown warning light).
Precautions
Be very careful when making electrical
circuit connections to the alternator, and note
the following:
a) When reconnecting wires to the alternator
from the battery, be sure to note the
polarity.
b) Before using arc-welding equipment to
repair any part of the vehicle, disconnect
the wires from the battery terminals and
from the alternator.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery. Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
c) Never start the engine with a battery
charger connected. Always disconnect
both battery cables before using a battery
charger.
d) Never disconnect cables from the battery
or from the alternator while the engine is
running.
e) The alternator is turned by an engine
drivebelt. Serious injury could result if
your hands, hair or clothes become
entangled in the belt with the engine
running.
f) Because the alternator is connected
directly to the battery, take care not to
short out the main terminal to earth.
g) Wrap a plastic bag over the alternator,
and secure it with rubber bands, before
steam-cleaning the engine.
14 Charging system- check
3
1If a malfunction occurs in the charging
circuit, don’t automatically assume that the
alternator is causing the problem. First check
the following items:
a) Check the drivebelt tension and condition
(see Chapter 1). Renew the drivebelt if it’s
worn or deteriorated.
b) Make sure the alternator mounting and
adjustment bolts are tight.
c) Inspect the alternator wiring harness and
the connectors at the alternator and
voltage regulator. They must be in good
condition and tight.
d) Check the fuses.
e) Start the engine and check the alternator
for abnormal noises (a shrieking or
squealing sound indicates a worn bearing,
but could also be due to a slipping
drivebelt - see a) above).f) Check the specific gravity of the battery
electrolyte. If it’s low, charge the battery
(doesn’t apply to maintenance-free
batteries).
g) Make sure the battery is fully-charged
(one bad cell in a battery can cause
overcharging by the alternator).
h) Disconnect the battery cables (negative
first, then positive). Inspect the battery
posts and the cable clamps for corrosion.
Clean them thoroughly if necessary (see
Chapter 1).
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery. Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
2With the ignition off, connect a 12 volt test
light between the battery negative post and
the disconnected negative cable clamp. If the
test light does not come on, refit the cable
and proceed to paragraph 4. If the test light
comes on, there is a short (drain) in the
electrical system of the vehicle. The short
must be repaired before the charging system
can be checked. Note: Accessories which are
always on (such as the clock or the radio
station memory) must be disconnected before
performing this check.
3Disconnect the alternator wiring harness. If
the test light now goes out, the alternator is
faulty. If the light stays on, remove each fuse
in turn until the light goes out (this will tell you
which component is shorting out).
4Using a voltmeter, check the battery
voltage with the engine off. It should be
approximately 12 volts.
5Start the engine and check the battery
voltage again. It should now be approximately
14 to 15 volts.
6Turn on the headlights. The voltage should
drop, and then come back up, if the charging
system is working properly.
7If the voltage reading is more than the
specified charging voltage, renew the voltage
regulator (refer to Section 16). If the voltage is
less, the alternator diode(s), stator or rotor
may be faulty, or the voltage regulator may be
malfunctioning.
8If there is no short-circuit causing battery
drain but the battery is constantly
discharging, then either the battery itself is
defective, the alternator drivebelt is loose (see
Chapter 1), the alternator brushes are worn,
dirty or disconnected (see Section 17), the
voltage regulator is malfunctioning (see
Section 16) or the diodes, stator coil or rotor
coil are defective. Repairing or renewing the
diodes, stator coil or rotor coil is beyond the
scope of the home mechanic. Either renew
Engine electrical systems 5•9
12.11 The sensor tip should be set at 1.0 ±
0.3 mm from the pulse wheel
5

6
Chapter 6
Engine management and emission control systems
Catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Electronic Control Unit (ECU) - removal and refitting . . . . . . . . . . . . 3
Evaporative emissions control (EVAP) system . . . . . . . . . . . . . . . . . 6
Evaporative emissions control system inspection . . . See Chapter 1
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Information sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Motronic engine management system self-diagnosis -
general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Positive crankcase ventilation (PCV) system . . . . . . . . . . . . . . . . . . 5
6•1
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty Contents
1 General information
To prevent pollution of the atmosphere
from incomplete combustion or evaporation
of the fuel, and to maintain good driveability
and fuel economy, a number of emission
control systems are used on these vehicles.
Not all of these systems are fitted to all
models, but they include the following:
Catalytic converter
Evaporative emission control (EVAP) system
Positive crankcase ventilation (PCV) system
Electronic engine management
The Sections in this Chapter include
general descriptions and checking
procedures within the scope of the home
mechanic, as well as component renewal
procedures (when possible) for each of the
systems listed above.
Before assuming that an emissions control
system is malfunctioning, check the fuel and
ignition systems carefully. The diagnosis of
some emission control devices requires
specialised tools, equipment and training. If
checking and servicing become too difficult,
or if a procedure is beyond your ability,
consult a dealer service department or other
specialist.This doesn’t mean, however, that emission
control systems are particularly difficult to
maintain and repair. You can quickly and
easily perform many checks, and do most of
the regular maintenance at home with
common tune-up and hand tools.
Pay close attention to any special
precautions outlined in this Chapter. It should
be noted that the illustrations of the various
systems may not exactly match the system
fitted on your vehicle because of
changes made by the manufacturer during
production.
2 Motronic engine management
system self-diagnosis-
general information
The Motronic engine management system
control unit (computer) has a built-in self-
diagnosis system, which detects malfunctions
in the system sensors and stores them as
fault codes in its memory. It is not possible
without dedicated test equipment to extract
these fault codes from the control unit.
However, the procedures given in Chapters 4
and 5 may be used to check individual
components and sensors of the Motronic
system. If this fails to pinpoint a fault, then the
vehicle should be taken to a BMW dealer, who
will have the necessary diagnostic
equipment to call up the fault codes from the
control unit. You will then have the
option to repair the fault yourself, or
alternatively have the fault repaired by the
BMW dealer.
3 Electronic control unit (ECU)
- removal and refitting
2
Removal
1The Electronic Control Unit (ECU) is located
either inside the passenger compartment
under the right-hand side of the facia panel on
3-Series models, or in the engine
compartment on the right-hand side on 5-
Series models (see Chapter 4).
2Disconnect the battery negative cable.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation code
before disconnecting the battery. Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
3First remove the access cover on models
with the ECU on the right-hand side of the
engine compartment (see Chapter 4).
4If the ECU is located inside the vehicle,
remove the access cover on the right-hand side.
5Unplug the electrical connectors from the
ECU.
6Remove the retaining bolts from the ECU
bracket.
7Carefully remove the ECU. Note: Avoid static
electricity damage to the ECU by wearing rubber
gloves, and do not touch the connector pins.
Refitting
8Refitting is a reversal of removal.
The most frequent cause of
emission system problems is
simply a leaking vacuum hose
or loose wire, so always
check the hose and wiring connections
first.

Refitting
7Refitting is the reverse of removal. Tighten
the nuts and bolts securely. Adjust the
drivebelt tension (see Chapter 1).
8Top-up the fluid level in the reservoir (see
Chapter 1) and bleed the system (see Sec-
tion 23).
23 Power steering system-
bleeding
1
1To bleed the power steering system, begin
by checking the power steering fluid level and
adding fluid if necessary (see Chapter 1).
2Raise and support the front of the vehicle
on axle stands.
3Turn the steering wheel from lock-to-lock
several times. Recheck the fluid level and top
up if necessary.
4Start the engine and run it at 1000 rpm or
less. Turn the steering wheel from lock-to-
lock again (three or four times) and recheck
the fluid level one more time. Note:On 5-Series E28 (“old-shape”) models, pump the
brake pedal five or six times before turning the
steering wheel. Once the fluid level remains
constant, continue turning the wheel back and
forth until no more bubbles appear in the fluid
in the reservoir.
5Lower the vehicle to the ground. Run the
engine and again turn the wheels from lock-
to-lock several more times. Recheck the fluid
level. Position the wheels straight-ahead.24 Steering wheel-
removal and refitting
1
Warning: If the vehicle is
equipped with an airbag, do not
attempt this procedure. Have it
performed by a dealer service
department or other qualified specialist, as
there is a risk of injury if the airbag is
accidentally triggered.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Removal
1Disconnect the battery negative cable.
2Using a small screwdriver, prise off the
BMW emblem in the centre of the steering
wheel.
3Remove the steering wheel nut, and mark
the relationship of the steering wheel hub to
the shaft (see illustration).
4On all 3-Series models, and on 1986 and
later 5-Series models, turn the ignition key to
the first position to unlock the ignition lock.
5Remove the steering wheel from thesteering shaft. If the wheel is difficult to
remove from the shaft, use a steering wheel
puller to remove it - don’t hammer on the
shaft.
Refitting
6Refitting is the reverse of removal. Be sure
to align the match marks you made on the
steering wheel and the shaft. Tighten the
steering wheel nut to the torque listed in this
Chapter’s Specifications.
25 Wheels and tyres-
general information
1
Note:For more information on care and
maintenance of tyres, refer to Chapter 1.
1All vehicles covered by this manual are
equipped with steel-belted radial tyres as
original equipment. Use of other types or
sizes of tyres may affect the ride and handling
of the vehicle. Don’t mix different types or
sizes of tyres, as the handling and braking
may be seriously affected. It’s recommended
that tyres be renewed in pairs on the same
axle; if only one new tyre is being fitted, be
sure it’s the same size, structure and tread
design as the other.
2Because tyre pressure has a substantial
effect on handling and wear, the pressure on
all tyres should be checked at least once a
month or before any extended trips (see
Chapter 1).
3Wheels must be renewed if they are bent,
heavily dented, leak air, or are otherwise
damaged.
4Tyre and wheel balance is important in the
overall handling, braking and performance of
the vehicle. Unbalanced wheels can adversely
affect handling and ride characteristics, as
well as tyre life. Whenever a new tyre is fitted,
the tyre and wheel should be balanced.
10•16 Suspension and steering systems
24.3 After removing the steering wheel
nut, mark the relationship of the steering
wheel to the steering shaft (arrowed) to
ensure proper alignment during
reassembly
22.6c Typical 5-Series power steering pump mounting bolts
(arrowed)22.6b . . . and mounting nut and bolt (arrowed)