1990 BMW 3 SERIES air filter

Caution: Do not overfill the
reservoir. If too much fluid is
added, remove the excess with a
clean syringe. Refit the cap.
7If frequent topping-up is needed, check the
power steering hoses and connections for
leaks and wear (see Section 10).
8Check the condition and tension of the
drivebelt (see Section 11).
8 Automatic transmission fluid
level check
1
Caution: The use of transmission
fluid other than the type listed in
this Chapter’s Specifications
could result in transmission
malfunctions or failure.
1The automatic transmission fluid should be
carefully maintained. Low fluid level can lead
to slipping or loss of drive, while overfilling
can cause foaming and loss of fluid. Either
condition can cause transmission damage.
2Since transmission fluid expands as it heats
up, the fluid level should only be checked
when the transmission is warm (at normal
operating temperature). If the vehicle has just
been driven over 20 miles (32 km), the
transmission can be considered warm. You
can also check the fluid level when the
transmission is cold. If the vehicle has not
been driven for over five hours and the fluid is
about room temperature (20°C), the
transmission is cold. However, the fluid level
is normally checked with the transmission
warm, to ensure accurate results.
Caution: If the vehicle has just
been driven for a long time at
high speed or in city traffic, in hot
weather, or if it has been pulling
a trailer, an accurate fluid level reading
cannot be obtained. Allow the trans-
mission to cool down for about 30 minutes.
3Immediately after driving the vehicle, park it
on a level surface, apply the handbrake and
start the engine. While the engine is idling,
depress the brake pedal and move theselector lever through all the gear ranges,
beginning and ending in Park.
4The automatic transmission dipstick tube is
located in the left rear corner of the engine
compartment.
5With the engine still idling, pull the dipstick
out of the tube (see illustration), wipe it off
with a clean rag, push it all the way back into
the tube and withdraw it again, then note the
fluid level.
6The level should be between the two marks
(see illustration). If the level is low, add the
specified automatic transmission fluid through
the dipstick tube - use a clean funnel,
preferably equipped with a fine mesh filter, to
prevent spills.
Caution: Be careful not to
introduce dirt into the
transmission when topping up.
7Add just enough of the recommended fluid
to fill the transmission to the proper level. It
takes about half a litre to raise the level from
the low mark to the high mark when the fluid
is hot, so add the fluid a little at a time, and
keep checking the level until it’s correct.
8The condition of the fluid should also be
checked along with the level. If the fluid is
black or a dark reddish-brown colour, or if it
smells burned, it should be changed (see
Section 28). If you are in doubt about its
condition, purchase some new fluid, and
compare the two for colour and smell.
9 Tyre rotation
1
1The tyres can be rotated at the specified
intervals, or whenever uneven wear is noticed.
However, bear in mind that if rotation
succeeds in making all the tyres wear evenly,
you will eventually have to renew all four at
once. Since the vehicle will be raised and the
wheels removed anyway, check the brakes
also (see Section 26). Note: Even if you don’t
rotate the tyres, at least check the wheel bolt
tightness.
2It is recommended that the tyres be rotatedin a specific pattern (see illustration)so that
their direction of rotation remains the same.
3Refer to the information in “Jacking and
towing”at the front of this manual for the
proper procedure to follow when raising the
vehicle and changing a tyre.
4The vehicle must be raised on a hoist or
supported on axle stands to get all four tyres
off the ground. Make sure the vehicle is safely
supported!
5After the rotation procedure is finished,
check and adjust the tyre pressures as
necessary, and be sure to check the wheel
bolt tightness.
10 Underbonnet hose check
and renewal
3
Warning: Renewal of air
conditioning hoses must be left
to a dealer service department or
air conditioning specialist having
the equipment to depressurise the system
safely. Never disconnect air conditioning
hoses or components until the system has
been depressurised.
General
1High temperatures under the bonnet can
cause deterioration of the rubber and plastic
hoses used for various systems. Periodic
inspection should be made for cracks, loose
clamps, material hardening, and leaks.
2Information specific to the cooling system
can be found in Section 22, while the braking
system is covered in Section 26.
3Most (but not all) hoses are secured with
clamps. Where clamps are used, check to be
sure they haven’t lost their tension, allowing
the hose to leak. If clamps aren’t used, make
sure the hose has not expanded and/or
hardened where it slips over the fitting,
allowing it to leak.
Vacuum hoses
4It’s quite common for vacuum hoses,
especially those in the emissions system, to
be colour-coded or identified by coloured
1•13
9.2 The tyre rotation pattern for these
models8.6 With the fluid hot, the level should be
kept between the two dipstick notches,
preferably near the upper one8.5 The automatic transmission fluid
dipstick (arrowed) is located near the
bulkhead on the left side of the engine
compartment
1
Every 6000 miles

stripes moulded into them. Various systems
require hoses with different wall thicknesses,
collapse resistance and temperature
resistance. When fitting new hoses, be sure
the new ones are made of the same material.
5Often the only effective way to check a
hose is to remove it completely from the
vehicle. If more than one hose is removed, be
sure to label the hoses and fittings to ensure
correct refitting.
6When checking vacuum hoses, be sure to
include any plastic T-fittings in the check.
Inspect the connections for cracks which
could cause leakage.
7A small piece of vacuum hose can be used
as a stethoscope to detect vacuum leaks.
Hold one end of the hose to your ear and
probe around vacuum hoses and fittings,
listening for the “hissing” sound characteristic
of a vacuum leak.
Warning: When probing with the
vacuum hose stethoscope, be
careful not to touch moving
engine components such as the
drivebelt, cooling fan, etc.
Fuel hoses
Warning: There are certain
precautions which must be taken
when servicing or inspecting fuel
system components. Work in a
well-ventilated area, and do not allow open
flames (cigarettes, appliance pilot lights,
etc.) or bare light bulbs near the work
area. Mop up any spills immediately, and
do not store fuel-soaked rags where they
could ignite. If you spill any fuel on your
skin, rinse it off immediately with soap and
water. When you perform any kind of work
on the fuel system, wear safety glasses,
and have a fire extinguisher on hand.
8The fuel hoses are usually under pressure,
so if any fuel hoses are to be disconnected,
be prepared to catch spilled fuel.
Warning: On vehicles equipped
with fuel injection, you must
depressurise the fuel system
before servicing the fuel hoses.
Refer to Chapter 4 for details.9Check all rubber fuel hoses for deterioration
and chafing. Check especially for cracks in
areas where the hose bends, and just before
connectors, such as where a hose attaches to
the fuel pump or fuel filter, for example.
10Only high-quality fuel hose should be
used. Never, under any circumstances, use
unreinforced vacuum hose, clear plastic
tubing or water hose for fuel hoses.
11Band-type clamps are commonly used on
fuel hoses. These clamps often lose their
tension over a period of time, and can be
“sprung” during removal. Renew all band-type
clamps with screw clamps whenever a hose is
renewed.
Metal lines
12Sections of metal line are often used
between the fuel pump and fuel injection
system. Check carefully to make sure the line
isn’t bent, crimped or cracked.
13If a section of metal line must be renewed,
use seamless steel tubing only, since copper
and aluminium tubing do not have the
strength necessary to withstand the vibration
caused by the engine.
14Check the metal brake lines where they
enter the master cylinder and brake
proportioning or ABS unit (if used) for cracks
in the lines and loose fittings. Any sign of
brake fluid leakage calls for an immediate
thorough inspection of the braking system.
Power steering hoses
15Check the power steering hoses for leaks,
loose connections and worn clamps. Tighten
loose connections. Worn clamps or leaky
hoses should be renewed.
11 Drivebelt check, adjustment
and renewal
1
Check
1The drivebelts, sometimes called V-belts or
simply “fan” belts, are located at the front of
the engine, and play an important role in the
overall operation of the vehicle and itscomponents. Due to their function and
material make-up, the belts are prone to
failure after a period of time, and should be
inspected and adjusted periodically to prevent
major engine damage.
2The number of belts used on a particular
vehicle depends on the accessories fitted.
Drivebelts are used to turn the alternator,
power steering pump, water pump, and air
conditioning compressor. Depending on the
pulley arrangement, a single belt may be used
to drive more than one of these components.
3With the engine switched off, open the
bonnet and locate the various belts at the
front of the engine. Using your fingers (and a
torch, if necessary), move along the belts,
checking for cracks and separation of the belt
plies. Also check for fraying and glazing,
which gives the belt a shiny appearance (see
illustration). Both sides of the belts should be
inspected, which means you will have to twist
each belt to check the underside.
4The tension of each belt is checked by
pushing firmly with your thumb and seeing
how much the belt moves (deflects). Measure
the deflection with a ruler (see illustration). A
good rule of thumb is that the belt should
deflect 6 mm if the distance from pulley
centre-to-pulley centre is between 180 and
280 mm. The belt should deflect 13 mm if the
distance from pulley centre-to-pulley centre is
between 300 and 400 mm.
Adjustment
5If it is necessary to adjust the belt tension,
either to make the belt tighter or looser, it is
done by moving a belt-driven accessory on its
bracket. (When the same belt drives more
than one accessory, normally only one
accessory is moved when making
adjustment.)
6For each component, there will be an
adjusting bolt and a pivot bolt. Both bolts
must be loosened slightly to enable you to
move the component. On some components,
the drivebelt tension can be adjusted by
turning an adjusting bolt after loosening the
lockbolt (see illustration).
7After the two bolts have been loosened,
1•14
11.6 Loosen the nut on the other end of
the adjuster bolt (arrowed) and turn the
bolt to increase or decrease tension on the
drivebelt11.4 Measuring drivebelt deflection with a
straightedge and ruler11.3 Here are some of the more common
problems associated with drivebelts
(check the belts very carefully to prevent
an untimely breakdown)
Every 6000 miles

move the component away from the engine to
tighten the belt, or towards the engine to
loosen the belt. Hold the accessory in
position, and check the belt tension. If it is
correct, tighten the two bolts until just tight,
then recheck the tension. If the tension is still
correct, tighten the bolts.
8It will often be necessary to use some sort
of lever to move the accessory while the belt
is adjusted. If this must be done to gain the
proper leverage, be very careful not to
damage the component being moved, or the
part being prised against.
Renewal
9To renew a belt, follow the instructions
above for adjustment, but remove the belt
from the pulleys.
10In some cases, you will have to remove
more than one belt, because of their
arrangement on the front of the engine.
Because of this, and the fact that belts will
tend to fail at the same time, it is wise to
renew all belts together. Mark each belt and
its appropriate pulley groove, so all renewed
belts can be fitted in their proper positions.
11It is a good idea to take the old belts with
you when buying new ones, in order to make
a direct comparison for length, width and
design.
12Recheck the tension of new belts after a
few hundred miles.
12 Engine idle speed and CO
level check and adjustment
4
Note:The engine should be at normal
operating temperature, with correct ignition
timing and valve clearances (where
adjustable). The air filter should be in good
condition, and all electrical components
(including the air conditioning, where fitted)
should be switched off.
Carburettor
1Connect a tachometer and exhaust gas
analyser (CO meter) to the engine.
2Start the engine and allow it to idle.
3Check that the idle speed is as given in the
Specifications. Adjustment of the idle speed is
only possible on the 2B4 carburettor. Turn the
carburettor idle speed adjustment screw until
the engine idles at the correct speed (see
illustration).
4If the idle speed is low on the 2BE
carburettor, and all wiring to the carburettor is
in good condition, it is possible to connect a
resistance into the control circuit. This should
be carried out by your BMW dealer.
5Check that the CO reading is as given in the
Specifications. If not, turn the carburettor idle
mixture adjustment screw until the mixture is
correct (see illustration).
L-Jetronic
6Connect a tachometer and CO meter to the
engine. BMW technicians use a special CO
tester with a probe connected into the
exhaust manifold, but the normal type of
tester which locates in the exhaust tailpipe
can be used instead. Note however that on
models with a catalytic converter, meaningful
CO readings will not be obtained at the
tailpipe.
7Start the engine and allow it to idle.
8Check that the idle speed is as given in
Specifications. If not, remove the tamperproof
cap from the throttle housing, and turn the idle
adjustment screw until the speed is correct.
9Check that the CO reading is as given in the
Specifications. The mixture control screw is
located on the airflow meter, and a specialtool (BMW number 13 1 060) may be required
to make the adjustment.
Motronic
10Connect a tachometer and CO meter to
the engine. BMW technicians use a special
CO tester with a probe connected into the
exhaust manifold, but the normal type of
tester which locates in the exhaust tailpipe
may be used instead. Note however that on
models with a catalytic converter, meaningful
CO readings will not be obtained at the
tailpipe.
11It is not possible to adjust the idle speed
manually, as the idle air stabiliser valve is
activated by the electronic control unit. If the
idle speed is not within the specified range
with the engine at normal operating
temperature, check for a leak in the air inlet
system, and also check the operation of the
idle air stabiliser valve (see Chapter 4).
12Check that the CO reading is as given in
the Specifications. If adjustment is required,
prise out the tamperproof plug from the
airflow meter, and turn the adjustment screw
to set the CO content (on some models, an
Allen key will be required). Fit a new
tamperproof plug on completion (see
illustrations).
1•15
12.12a Removing the tamperproof plug
from the airflow meter
12.5 Mixture adjustment screw (2) on the
2B4 carburettor
12.3 Idle speed adjustment screw on the
2B4 carburettor (shown with the
carburettor removed)
12.12b Adjusting the CO on the Motronic
system
1
Every 6000 miles

drag when the feeler gauge is moved back
and forth.
6If the gap is too large or too small, loosen
the locknut, insert a hook made from large-
diameter metal wire, and rotate the eccentric
to obtain the correct gap (see illustration).
7Once the gap has been set, hold the
eccentric in position with the hook, and
retighten the locknut securely. Recheck the
clearance - sometimes it’ll change slightly
when the locknut is tightened. If so, re-adjust
until it’s correct.
8On the M10 engine, the valves are adjusted
in the firing order, which is 1-3-4-2. After
adjusting No 1 cylinder valves, rotate the
crankshaft half a turn (180º), then check and
adjust the valves on No 3 cylinder. Repeat the
procedure on the remaining cylinders.
9On M20 and M30 engines, the valves are
adjusted following the firing order, which is
1-5-3-6-2-4. After adjusting No 1 cylinder
valves, rotate the crankshaft a third of a turn
(120º), then check and adjust the valves on No
5 cylinder. Repeat the procedure for the
remaining cylinders.
10Refit the valve cover (use a new gasket)
and tighten the mounting nuts evenly and
securely.
11Start the engine and check for oil leakage
between the valve cover and the cylinder
head.19 Throttle linkage -
check and lubrication
1
1The throttle linkage should be checked and
lubricated periodically to ensure its proper
operation.
2Check the linkage to make sure it isn’t
binding.
3Inspect the linkage joints for looseness, and
the connections for corrosion and damage,
renewing parts as necessary (see
illustration).
4Lubricate the connections with spray
lubricant or lithium-based grease.
20 Air filter renewal
1
Carburettor engines
1Release the spring clips, then unscrew the
centre nut and lift off the cover.
2Remove the air filter element, and wipe
clean the air cleaner body and cover
3Fit the new air filter element, then refit the
cover using a reversal of the removal
procedure.
Fuel injection engines
4Loosen the clamp on the air intake duct,
and detach the duct (see illustration).5Release the air cleaner cover retaining clips
(see illustration).
6Rotate the cover up, lift it off and lift the
element out, noting which way round it is
fitted (see illustrations).
7Wipe the inside of the air cleaner housing
with a clean cloth, then fit the new element. If
the element is marked TOP, be sure the
marked side faces up.
8Refit the cover and secure the clips.
9Connect the air duct and tighten the clamp
screw.
21 Fuel system check
1
Warning: Fuel is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area. Don’t work in a
garage where a natural gas-type appliance
(such as a water heater or clothes dryer)
with a pilot light is present. Work in a well-
ventilated area. If you spill any fuel on your
skin, rinse it off immediately with soap and
water. When you perform any kind of work
on the fuel system, wear safety glasses,
and have a fire extinguisher on hand. Mop
up spills immediately, but do not store
fuel-soaked rags where they could ignite.
1If you smell fuel while driving or after the
vehicle has been sitting in the sun, inspect the
fuel system immediately.
2Remove the fuel filler cap and inspect it for
damage and corrosion. The gasket should
have an unbroken sealing imprint. If the
gasket is damaged or corroded, fit a new cap.
3Inspect the fuel feed and return lines for
cracks. Make sure that the connections
between the fuel lines and the carburettor or
fuel injection system, and between the fuel
lines and the in-line fuel filter, are tight.
Warning: On fuel injection
models, the fuel system must be
depressurised before servicing
fuel system components, as
outlined in Chapter 4.
1•20
20.6b . . . and lift the air filter
element out20.6a Rotate the cover
upwards . . .
20.5 Use a screwdriver to detach the air
cleaner cover clips20.4 Detach the duct from the air cleaner
housing19.3 Check and lubricate the throttle
linkage at the points shown (arrowed) -
fuel injection engine shown
Every 12 000 miles

material is bonded to a metal plate or shoe -
the metal portion is not included in this
measurement. Always renew the pads on
both sides of the vehicle (in axle sets), even if
only one pad of the four is worn, or uneven
braking may result.
12Remove the calipers without
disconnecting the brake hoses (see Chap-
ter 9).
13Check the condition of the brake disc.
Look for score marks, deep scratches and
overheated areas (they will appear blue or
discoloured). If damage or wear is noted, the
disc can be removed and resurfaced by an
engineering workshop; otherwise, it will have
to be renewed. In either case, both discs
should be involved, even if only one is worn.
Refer to Chapter 9 for more detailed
inspection and repair procedures.
Drum brakes
14Refer to Chapter 9 and remove the rear
brake drums.
15Note the thickness of the lining material
on the rear brake shoes, and look for signs of
contamination by brake fluid or grease (see
illustration). If the material is within 2.0 mm of
the recessed rivets or metal shoes, renew the
brake shoes. The shoes should also be
renewed if they are cracked, glazed (shiny
lining surfaces), or contaminated with brake
fluid or grease. See Chapter 9 for the renewal
procedure.
16Check the shoe return and hold-down
springs and the adjusting mechanism. Make
sure all these components are fitted correctly,and are in good condition. Deteriorated or
distorted springs, if not renewed, could allow
the linings to drag and wear prematurely.
17Check the wheel cylinders for leakage by
carefully peeling back the rubber boots. Slight
moisture behind the boots is acceptable. If
brake fluid is noted behind the boots or if it
runs out of the wheel cylinder, the wheel
cylinders must be overhauled or renewed (see
Chapter 9).
18Check the drums for cracks, score marks,
deep scratches and high spots, which will
appear as small discoloured areas. If
imperfections cannot be removed with emery
cloth, both drums must be resurfaced by a
specialist (see Chapter 9 for more detailed
information).
19Refer to Chapter 9 and fit the brake
drums.
20Refit the wheels, but don’t lower the
vehicle yet.
Handbrake
21The easiest, and perhaps most obvious,
method of checking the handbrake is to park
the vehicle on a steep hill with the handbrake
applied and the transmission in Neutral (stay
in the vehicle while performing this check). If
the handbrake doesn’t prevent the vehicle
from rolling, refer to Chapter 9 and adjust it.
27 Wiper blades -
check and renewal
1
1Road film can build up on the wiper blades
and affect their efficiency, so they should bewashed regularly with a mild detergent
solution.
Check
2The wiper and blade assembly should be
inspected periodically. If inspection reveals
hardened or cracked rubber, renew the wiper
blades. If inspection reveals nothing unusual,
wet the windscreen, turn the wipers on, allow
them to cycle several times, then switch them
off. An uneven wiper pattern across the glass,
or streaks over clean glass, indicate that the
blades should be renewed.
3The operation of the wiper mechanism can
loosen the retaining nuts, so they should be
checked and tightened, as necessary, at the
same time the wiper blades are checked (see
Chapter 12 for further information regarding
the wiper mechanism).
Wiper blade renewal
4Pull the wiper/blade assembly away from
the glass.
5Press the retaining tab in, and slide the
blade assembly down the wiper arm (see
illustration).
6If you wish to renew the blade rubbers
separately, detach the end of the rubber from
the wiper blade frame, then slide the rubber
out of the frame (see illustration).
7Compare the new rubber with the old for
length, design, etc.
8Slide the new rubber into place, and insert
the end in the wiper blade frame to lock it in
place.
9Refit the blade assembly on the arm, then
wet the glass and check for proper operation.
1•23
27.6 Detach the end of the wiper element
from the end of the frame, then slide the
element out27.5 Press the retaining tab in, then slide
the wiper blade assembly down and out of
the hook in the end of the wiper arm26.15 If the lining is bonded to the brake
shoe, measure the lining thickness from
the outer surface to the metal shoe, as
shown here (A); if the lining is riveted to
the shoe, measure from the lining outer
surface to the rivet head
1
Every 12 000 miles
Every 24 000 miles or 2 years, whichever comes first
28 Automatic transmission fluid
and filter change
1
1At the specified intervals, the transmission
fluid should be drained and renewed. Since
the fluid will remain hot long after driving,perform this procedure only after the engine
has cooled down completely.
2Before beginning work, purchase the
specified transmission fluid (see “Lubricants
and fluids”at the beginning of this Chapter)
and a new filter.
3Other tools necessary for this job include axle
stands or ramps to support the vehicle in araised position, a drain pan capable of holding at
least 4.5 litres, and newspapers and clean rags.
4Raise the vehicle and support it securely.
5Loosen the dipstick tube collar, then detach
the dipstick tube and let the fluid drain (see
illustrations).
6Remove the transmission sump mounting
bolts and brackets (see illustration).

7Detach the sump from the transmission and
lower it, being careful not to spill the
remaining fluid (see illustration).
8Carefully clean the sump-to-transmission
contact surface.
9Pour the fluid from the sump into a suitable
container, then clean the sump with solvent
and dry it with compressed air. Be sure to
clean any metal filings from the magnet, if
applicable.
10Remove the filter from inside the
transmission (see illustrations).
11Fit the O-ring and a new filter, being sure
to tighten the bolts securely.
12Make sure that the sump gasket contact
surfaces are clean, then fit the new gasket.
Offer the sump up to the transmission, and
refit the brackets and bolts. Working aroundthe sump, tighten each bolt a little at a time
until the torque listed in this Chapter’s Specifi-
cations is reached. Don’t overtighten the
bolts! Connect the dipstick tube, and tighten
the collar securely.
13Lower the vehicle, and add the specified
amount of fluid through the filler tube (see
Section 8).
14With the transmission in Park and the
handbrake applied, run the engine at fast idle,
but don’t race it.
15Move the gear selector through each
position, and back to Park. Check the fluid
level.
16Check under the vehicle for leaks after the
first few trips.
29 Cooling system -draining,
flushing and refilling
1
Warning: Do not allow antifreeze
to come in contact with your skin,
or with the painted surfaces of the
vehicle. Rinse off spills
immediately with plenty of water. Antifreeze
is highly toxic if ingested. Never leave
antifreeze lying around in an open container
or in puddles on the floor; children and pets
are attracted by its sweet smell, and may
drink it. Check with local authorities about
disposing of used antifreeze. Local
collection centres may exist to see that
antifreeze is disposed of safely.1Periodically, the cooling system should be
drained, flushed and refilled. This will restore
the effectiveness of the antifreeze mixture and
prevent formation of rust and corrosion, which
can impair the performance of the cooling
system and cause engine damage. When the
cooling system is serviced, all hoses and the
radiator cap should be checked and renewed
if necessary.
Draining
2If the vehicle has just been driven, wait
several hours to allow the engine to cool down
before beginning this procedure.
3Once the engine is completely cool, remove
the expansion tank cap or radiator cap. If the
cap must be removed while the engine is still
warm, unscrew it slowly, and take adequate
precautions to avoid scalding.
4Move a large container under the radiator to
catch the coolant. Where a drain plug is fitted,
unscrew it (a pair of pliers or screwdriver may
be required to turn it, depending on the
model) (see illustration). Where there is no
drain plug, it will be necessary to disconnect
the bottom hose from the radiator.
5While the coolant is draining, check the
condition of the radiator hoses, heater hoses
and clamps (see Section 21 if necessary).
6Renew any damaged clamps or hoses (see
Chapter 3 for detailed renewal procedures).
1•24
28.10c Remove the O-ring from the
transmission. If it is in good condition,
clean it and transfer it to the new fluid
filter; otherwise, renew it
28.10b . . . then remove the fluid filter from
the transmission28.10a Use a Torx key to remove the filter
bolts . . .
28.7 Lower the sump from the
transmission
28.6 Use a socket and extension to
remove the bolts and brackets28.5b Detach the tube and let the fluid
drain28.5a Unscrew the dipstick tube collar
Every 24 000 miles

Flushing
7Once the system is completely drained,
flush the radiator with fresh water from a
garden hose until the water runs clear at the
drain or bottom hose. If the radiator is
severely corroded, damaged or leaking, it
should be removed (see Chapter 3) and taken
to a radiator repair specialist.
8Flushing in this way will remove sediments
from the radiator, but will not remove rust and
scale from the engine and cooling tube
surfaces. These deposits can be removed by
using a chemical cleaner. Follow the
procedure outlined in the cleaner
manufacturer’s instructions. Remove the
cylinder block drain plug before flushing the
engine.
9On models so equipped, remove the
overflow hose from the coolant recovery
reservoir. Drain the reservoir and flush it with
clean water, then reconnect the hose.
Refilling
10Tighten the radiator drain plug, or
reconnect the radiator bottom hose. Refit and
tighten the cylinder block drain plug.
Four-cylinder engines
11Slowly add new coolant (a 40%/60%
mixture of antifreeze to water) to the radiator
until it is full. Add coolant to the reservoir up
to the lower mark.
12Leave the radiator cap off, and run the
engine in a well-ventilated area until the
thermostat opens (coolant will begin flowing
through the radiator, and the upper radiator
hose will become hot).
13Turn the engine off, and let it cool. Add
more coolant mixture to bring the coolant
level back up to the lip on the radiator filler
neck. On the M40 engine, unscrew the bleed
screw from the top of the radiator, and add
coolant until it comes out of the bleed screw
hole. Refit and tighten the bleed screw.
14Squeeze the upper radiator hose to expel
air, then add more coolant mixture if
necessary. Refit the radiator cap.
15Start the engine, allow it to reach normal
operating temperature, and check for leaks.
Six-cylinder engines
16Loosen the bleed screw in the thermostat
housing (see illustration)
17Fill the radiator with a 40%/60% solution
of antifreeze and water until it comes out of
the bleed screw opening. Tighten the bleed
screw.
18Refit the radiator cap, and run the engine
until the thermostat opens (the upper radiator
hose will become hot). Slowly loosen the
bleed screw until no bubbles emerge, then
tighten the screw.
19Repeat the procedure until the air is bled
from the system.
30 Fuel filter renewal
1
Warning: Fuel is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area. Don’t work in a
garage where a natural gas-type appliance
(such as a water heater or clothes dryer)
with a pilot light is present. If you spill any
fuel on your skin, rinse it off immediately
with soap and water. When you perform
any kind of work on the fuel system, wear
safety glasses, and have a fire
extinguisher on hand.
1On fuel injection engines, depressurise the
fuel system (see Chapter 4).
2The fuel filter is located in the engine
compartment on the bulkhead, or under the
vehicle adjacent to the fuel tank.
3Because on some models the filter is
located adjacent to the starter motor, fuel
could leak onto the electrical connections. For
safety reasons, therefore, disconnect the
battery negative cable before beginning work.
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.
4Place a pan or rags under the fuel filter to
catch any spilled fuel. If suitable hose clamps
are available, clamp the inlet and outlet hoses.
5 Detach the hoses and remove the bracket
screws/nuts, then remove the filter and where
applicable the bracket assembly (see
illustration).
6Detach the filter from the bracket.
7Refitting is the reverse of removal. Be sure
the arrow on the filter points in the direction of
fuel flow.
31 Manual transmission
lubricant change
1
1Tools necessary for this job include axle
stands to support the vehicle in a raised
position, an Allen key to remove the drain
plug, a drain pan, newspapers and clean rags.
The correct amount of the specified lubricant
should also be available (see “Lubricants and
fluids”at the start of this Chapter).
2The lubricant should be drained when it is
hot (ie immediately after the vehicle has been
driven); this will remove any contaminants
better than if the lubricant were cold. Because
1•25
30.5 To renew the fuel filter, disconnect
the hoses (A), then unscrew the nut (B) and
detach the filter from the bracket (fuel
injection type shown)29.16 The bleed screw (arrowed) is
located on the thermostat housing (six-
cylinder models)29.4 Radiator drain plug location
(arrowed) - not fitted to all models
31.5 Use an Allen key to remove the drain
plug (arrowed) from the bottom of the
transmission
1
Every 24 000 miles

2A
General
Displacement
3-series, E30 body style
316i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1596 cc (M40/4-cylinder engine)
316 (1983 to 1988) and 318i (1983 to 1987) . . . . . . . . . . . . . . . . 1766 cc (M10/4-cylinder engine)
318i (1987 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1796 cc (M40/4-cylinder engine)
320i (1987 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1990 cc (M20/6-cylinder engine)
325i (1987 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2494 cc (M20/6-cylinder engine)
5-series, E28 body style (“old-shape”)
518 (1981 to 1985) and 518i (1985 to 1988) . . . . . . . . . . . . . . . . 1766 cc (M10/4-cylinder engine)
525i (1981 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2494 cc (M30/6-cylinder engine)
528i (1981 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2788 cc (M30/6-cylinder engine)
535i (1985 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3430 cc (M30/6-cylinder engine)
M535i (1985 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3430 cc (M30/6-cylinder engine)
5-series, E34 body style (“new-shape”)
518i (1990 to 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1796 cc (M40/4-cylinder engine)
520i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1990 cc (M20/6-cylinder engine)
525i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2494 cc (M20/6-cylinder engine)
530i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2986 cc (M30/6-cylinder engine)
535i (1988 to 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3430 cc (M30/6-cylinder engine)
Firing order
Four-cylinder engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3-4-2
Six-cylinder engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5-3-6-2-4
Lubrication system
Oil pressure (all engines)
At idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 to 2.0 bars
Running (for example, at 4000 rpm) . . . . . . . . . . . . . . . . . . . . . . . . . . 4 bars or above (typically)
Oil pump rotor clearance - M40 engine
(body-to-outer rotor/outer rotor-to-inner rotor) . . . . . . . . . . . . . . . . . . . 0.12 mm to 0.20 mm
Oil pump pressure relief valve spring length - M40 engine . . . . . . . . . . 84.1 mm
Chapter 2 Part A:
In-car engine repair procedures
Camshaft - removal, inspection and refitting . . . . . . See Chapter 2B
Compression check . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 2B
Crankshaft rear oil seal - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Cylinder head - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 12
Cylinder head - dismantling and inspection . . . . . . . See Chapter 2B
Drivebelt check, adjustment and renewal . . . . . . . . See Chapter 1
Engine - removal and refitting . . . . . . . . . . . . . . . . . See Chapter 2B
Engine mountings - check and renewal . . . . . . . . . . . . . . . . . . . . . . 17
Engine oil and filter change . . . . . . . . . . . . . . . . . . . See Chapter 1
Engine overhaul - general information . . . . . . . . . . . See Chapter 2B
Exhaust manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . 6
Flywheel/driveplate - removal and refitting . . . . . . . . . . . . . . . . . . . 15
Front oil seals - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Intake manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 5Oil pump - removal, inspection and refitting . . . . . . . . . . . . . . . . . . 14
Repair operations possible with the engine in the vehicle . . . . . . . . 2
Rocker arm and shaft assembly - dismantling, inspection
and reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 2B
Spark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Sump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Timing belt and sprockets - removal, inspection and refitting . . . . . 10
Timing belt covers - removal and refitting . . . . . . . . . . . . . . . . . . . . . 9
Timing chain and sprockets - removal, inspection and refitting . . . . 8
Timing chain covers - removal and refitting . . . . . . . . . . . . . . . . . . . 7
Top Dead Centre (TDC) for No 1 piston - locating . . . . . . . . . . . . . . 3
Valve clearance check and adjustment . . . . . . . . . . . See Chapter 1
Valve cover - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Valves - servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 2B
2A•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