1990 BMW 5 SERIES clock

0•8Roadside Repairs
Jacking and wheel
changing
The jack supplied with the vehicle should
be used only for raising the vehicle when
changing a tyre or placing axle stands under
the frame.
Warning:Never crawl under the
vehicle or start the engine when
this jack is being used as the
only means of support.
When changing a wheel, the vehicle should
be on level ground, with the handbrake firmly
applied, and the wheels chocked. Select
reverse gear (manual transmission) or Park
(automatic transmission). Prise off the hub
cap (if equipped) using the tapered end of the
wheel brace. Loosen the wheel bolts half a
turn, leaving them in place until the wheel is
raised off the ground.
Position the head of the jack under the side
of the vehicle, making sure it engages with thepocket made for this purpose (just behind the
front wheel, or forward of the rear wheel).
Engage the wheel brace handle and turn it
clockwise until the wheel is raised off the
ground. Unscrew the bolts, remove the wheel
and fit the spare.
Refit the wheel bolts and tighten them
finger-tight. Lower the vehicle by turning the
wheel brace anti-clockwise. Remove the jack
and tighten the bolts in a diagonal pattern to
the torque listed in the Chapter 1
Specifications. If a torque wrench is not
available, have the torque checked by a BMW
dealer or tyre fitting specialist as soon as
possible. Refit the hubcap.
Towing
Vehicles with manual transmission can be
towed with all four wheels on the ground, if
necessary. Automatic transmission-equipped
vehicles can only be towed with all fourwheels on the ground providing that the
speed does not exceed 35 mph and the
distance is not over 50 miles, otherwise
transmission damage can result. For
preference, regardless of transmission type,
the vehicle should be towed with the driven
(rear) wheels off the ground.
Proper towing equipment, specifically
designed for the purpose, should be used,
and should be attached to the main structural
members of the vehicle, not to the bumpers or
bumper brackets. Sling-type towing
equipment must notbe used on these
vehicles.
Safety is a major consideration while
towing. The handbrake should be released,
and the transmission should be in neutral. The
steering must be unlocked (ignition switch
turned to position “1”). Remember that
power-assisted steering (where fitted) and the
brake servo will not work with the engine
switched off.
Jacking, towing and wheel changing

Every 6000 miles or 6 months, whichever comes first
1•11
6.17a Unscrew the bolt . . .
1
Every 6000 miles
6 Engine oil and filter change
1
Warning: Prolonged skin contact
with used engine oil is
hazardous. Use a barrier cream
and wear gloves during this procedure.
Change out of oil-soaked clothing
immediately.
1Make sure that you have all the necessary
tools before you begin this procedure (see
illustration). You should also have plenty of rags
or newspapers handy for mopping up oil spills2Start the engine and allow it to reach
normal operating temperature - oil and sludge
will flow more easily when warm. If new oil, a
filter or tools are needed, use the vehicle to go
and get them, thus warming up the engine oil
at the same time.
3Park on a level surface, and switch off the
engine when it’s warmed up. Remove the oil
filler cap from the valve cover.
4Access to the oil drain plug and filter will be
improved if the vehicle can be lifted on a hoist,
driven onto ramps, or supported by axle
stands.
Warning: DO NOT work under a
vehicle supported only by a
hydraulic or scissors-type jack -
always use axle stands!
5If you haven’t changed the oil on this
vehicle before, get under it, and locate the
drain plug and the oil filter. Note that on some
engines, the oil filter is located on the top left-
hand side of the engine. The exhaust
components will be hot as you work, so note
how they are routed to avoid touching them.
6Being careful not to touch the hot exhaust
components, position a drain pan under the
plug in the bottom of the engine.
7Clean the area around the plug, then
remove the plug (see illustration). It’s a good
idea to wear a rubber glove while unscrewing
the plug the final few turns, to avoid being
scalded by hot oil. Hold the drain plug againstthe threads as you unscrew it, then pull it
away from the drain hole suddenly. This will
place your arm out of the way of the hot oil, as
well as reducing the chances of dropping the
drain plug into the drain pan.
8It may be necessary to move the drain pan
slightly as oil flow slows to a trickle. Inspect
the old oil for the presence of metal particles,
which could give early warning of engine
wear.
9After all the oil has drained, wipe off the
drain plug with a clean rag. Any small metal
particles clinging to the plug would
immediately contaminate the new oil.
10Refit the plug and tighten it securely. Use
a new washer if necessary.
11Move the drain pan into position under the
oil filter.
Canister-type oil filter
12Loosen the spin-off type oil filter by
turning it anti-clockwise with a filter spanner.
Any standard filter spanner will work.
13Sometimes the spin-off type oil filter is
screwed on so tightly that it can’t be easily
loosened. If it is, punch a metal bar or long
screwdriver directly through it, and use it as a
T-bar to turn the filter. Be prepared for oil to
spurt out of the canister as it’s punctured.
14Once the filter is loose, use your hands to
unscrew it from the block. Just as the filter is
detached from the block, immediately tilt the
open end up to prevent oil inside the filter
from spilling out.
15Using a clean rag, wipe off the mounting
surface on the block. Also, make sure that
none of the old sealing ring remains stuck to
the mounting surface. It can be removed with
a scraper if necessary.
16Compare the old filter with the new one,
to make sure they are the same type. Smear
some engine oil on the rubber sealing ring of
the new filter, and screw it into place (see
illustration). Overtightening the filter will
damage the sealing ring, so don’t use a filter
spanner. Most filter manufacturers
recommend tightening the filter by hand only.
Normally, they should be tightened three-
quarters of a turn after the sealing ring
contacts the block, but be sure to follow the
directions on the filter or container.
6.1 These tools are required when
changing the engine oil and filter
1 Drain pan- It should be fairly shallow in
depth, but wide enough to prevent spills
2 Rubber gloves- When removing the drain
plug and filter, you will get oil on your
hands (the gloves will prevent burns)
3 Socket bar - Sometimes the oil drain plug
is tight, and a long bar is needed to loosen
it. The correct-size ring spanner may work
just as well
4 Socket- To be used with the bar or a
ratchet (must be the correct size to fit the
drain plug - six-point preferred)
5 Filter spanner - This is a metal band-type
spanner, which requires clearance around
the filter to be effective. This tool is not
required on all engines.
6 Filter spanner- This type fits on the bottom
of the filter and can be turned with a ratchet
or breaker bar (different-size spanners are
available for different types of filters) This
tool is not required on all engines.
6.7 Using a ring spanner to remove the oil
drain plug
6.16 Lubricate the oil filter sealing ring
with clean engine oil before refitting the
filter on the engine
Frequent oil changes are the
most important preventive
maintenance procedures that
can be done by the home
mechanic. As engine oil ages, it
becomes diluted and contaminated,
which leads to premature engine wear.

Cartridge-type oil filter
17Some models are equipped with a
cartridge-type oil filter. Unscrew the bolt,
remove the cover, and lift the filter out (see
illustrations).
18Compare the new cartridge with the old
one, to make sure they are the same type,
then lower it into the housing.
19Using a clean rag, wipe off the mounting
surface of the housing and cover. If necessary,
renew the rubber O-ring (see illustration).
Smear some clean oil on the O-ring and refit
the cover and bolt. Tighten the bolt securely.
All models
20Remove all tools and materials from under
the vehicle, being careful not to spill the oil
from the drain pan, then lower the vehicle.
21Add new oil to the engine through the oil
filler cap in the valve cover. Use a funnel to
prevent oil from spilling onto the top of the
engine. Pour the specified quantity of fresh oil
into the engine. Wait a few minutes to allow the
oil to drain into the sump, then check the level
on the dipstick (see Section 4 if necessary). If
the oil level is correct, refit the filler cap.
22Start the engine and run it for about a
minute. The oil pressure warning light may
take a few seconds to go out while the new
filter fills with oil; don’t rev the engine while
the light is on. While the engine is running,
look under the vehicle, and check for leaks at
the sump drain plug and around the oil filter. Ifeither one is leaking, stop the engine and
tighten the plug or filter slightly.
23Wait a few minutes, then recheck the level
on the dipstick. Add oil as necessary.
24During the first few days after an oil
change, make it a point to check frequently
for leaks and proper oil level.
25The old oil drained from the engine cannot
be re-used in its present state, and should be
discarded. Oil reclamation centres and some
service stations will accept the oil, which can
be recycled. After the oil has cooled, it can be
transferred into a container for transport to a
disposal site.
7 Power steering fluid level
check
1
1Check the power steering fluid level
periodically to avoid steering system
problems, such as damage to the pump.
Proceed as follows.Caution: Do not hold the steering
wheel against either stop (full-left
or full-right lock) for more than
five seconds. If you do, the power
steering pump could be damaged.
2On some models, the power steering fluid
reservoir is located on the left side of the
engine compartment, and has a twist-off cap
with an integral fluid level dipstick (see
illustration). Other models use a hydraulic
power steering and brake servo system which
combines the fluid in one reservoir, located at
the right rear corner of the engine
compartment.
3Park the vehicle on level ground, and apply
the handbrake.
4On models with a fluid dipstick, run the
engine until it has reached normal operating
temperature. With the engine at idle, turn the
steering wheel back and forth several times to
get any air out of the steering system. Switch
off the engine, remove the cap by turning it
anti-clockwise, wipe the dipstick clean, and
refit the cap. Remove the cap again, and note
the fluid level. It must be between the two
lines (see illustration).
5On hydraulic servo models, pump the brake
pedal about ten times or until the pedal is firm.
Remove the nut, lift the cap off, and make
sure the fluid is within 6.0 mm of the top of the
reservoir.
6Add small amounts of fluid until the level is
correct (see illustration).
1•12
7.6 Adding fluid to the power steering
reservoir7.4 The power steering fluid level should
be kept between the two arrows near the
upper step on the dipstick7.2 The power steering fluid reservoir
(arrowed) is located on the left side of the
engine compartment
6.19 Renewing the rubber O-ring in the
cover6.17c . . . and lift out the cartridge
Every 6000 miles
6.17b . . . remove the cover . . .
Note: It is
antisocial and
illegal to dump
oil down the
drain. To find
the location of
your local oil
recycling
bank, call this
number free.

5With the engine cool, remove the HT lead
from one spark plug. Do this by grabbing the
connector at the end of the wire, not the lead
itself (see illustration). Sometimes it is
necessary to use a twisting motion while the
connector and HT lead are pulled free.
6If compressed air is available, use it to blow
any dirt or foreign material away from the
spark plug area. A common bicycle pump will
also work. The idea here is to eliminate the
possibility of debris falling into the cylinder as
the spark plug is removed.
7Place the spark plug socket over the plug,
and remove it from the engine by turning it
anti-clockwise (see illustration).
8Compare the spark plug with those shown
in the accompanying photos to get an
indication of the overall running condition of
the engine.
9Apply a little copper-based anti-seize
compound to the threads of the new spark
plug. Locate the plug into the head, screwing
it in with your fingers until it no longer turns,
then tighten it with the socket. If available, use
a torque wrench to tighten the plug to ensure
that it is seated correctly. The correct torque
figure is included in this Chapter’s Specifi-
cations.10Before pushing the HT lead onto the end of
the plug, inspect it as outlined in Section 15.
11Attach the HT lead to the new spark plug,
again using a twisting motion on the
connector until it is firmly seated on the spark
plug.
12Follow the above procedure for the
remaining spark plugs, renewing them one at
a time to prevent mixing up the spark plug HT
leads.
15 Spark plug HT leads,
distributor cap and rotor -
check and renewal
1
1The spark plug HT leads should be checked
at the recommended intervals, and whenever
new spark plugs are fitted in the engine.
2Begin this procedure by making a visual
check of the spark plug HT leads while the
engine is running. In a darkened garage (make
sure there is ventilation) start the engine and
observe each HT lead. Be careful not to come
into contact with any moving engine parts. If
there is a break in the wire, you will see arcing
or a small spark at the damaged area. If arcing
is noticed, make a note to obtain new HT
leads, then allow the engine to cool.
3Disconnect 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.
4The HT leads should be inspected one at a
time to prevent mixing up the firing order,
which is essential for proper engine operation.
5Disconnect the HT lead from the spark
plug. Do not pull on the lead itself, only on the
connector.
6Inspect inside the connector for corrosion,
which will look like a white crusty powder.
Push the HT lead and connector back onto
the end of the spark plug. It should be a tight
fit on the plug end. If it is not, remove the lead
and use pliers to carefully crimp the metal
terminal inside the connector until it fits
securely on the end of the spark plug.
7Using a clean rag, wipe the entire length of
the HT lead to remove any built-up dirt and
grease. Once the lead is clean, check for
burns, cracks and other damage. Do not bend
the lead excessively, since the conductor
might break.
8Disconnect the HT lead from the distributor.
Again, pull only on the connector. Check for
corrosion and a tight fit in the same manner as
the spark plug end. Renew the HT lead in the
distributor if necessary.
9Check the remaining spark plug HT leads,
making sure they are securely fastened at the
distributor and spark plug when the check is
complete.
10If new spark plug HT leads are required,
purchase a set for your specific engine model.
Lead sets are available pre-cut, with the
connectors already fitted. Remove and renew
the HT leads one at a time, to avoid mix-ups
in the firing order.
11Loosen the screws or detach the clips and
remove the distributor cap (see illustration).
Remove the screws (if applicable) and pull the
rotor off the shaft (see illustration). Check the
distributor cap and rotor for wear. Look for
cracks, carbon tracks and worn, burned or
loose contacts (see illustrations). Renew the
cap and rotor if defects are found. It is
common practice to fit a new cap and rotor
whenever new spark plug HT leads are fitted.
When fitting a new cap, remove the HT leads
from the old cap one at a time, and attach
1•18
15.11b Use an Allen key to remove the
screws, then lift the rotor off the shaft
(later models)15.11a On later models, loosen the screws
and detach the distributor cap up so you
can inspect the inside
14.7 Use a socket spanner with an
extension to unscrew the spark plugs14.5 When removing the spark plug HT
leads, pull only on the connector
Every 12 000 miles
Where there might be difficulty in
inserting the spark plugs into the spark
plug holes, or the possibility of cross-
threading them into the head, a short
piece of rubber or plastic tubing can be
fitted over the end of the spark plug.
The flexible tubing will act as a universal
joint to help align the plug with the plug
hole, and should the plug begin to
cross-thread, the hose will slip on the
spark plug, preventing thread damage.

1 General information
This Part of Chapter 2 is devoted to in-
vehicle engine repair procedures. All
information concerning engine removal and
refitting and engine block and cylinder head
overhaul can be found in Chapter 2B.
The following repair procedures are based
on the assumption that the engine is still fitted
in the vehicle. If the engine has been removed
from the vehicle and mounted on a stand,
many of the steps outlined in this Part of
Chapter 2 will not apply.
The Specifications included in this Part of
Chapter 2 apply only to the procedures
contained in this Part. Chapter 2B contains
the Specifications necessary for cylinder head
and engine block rebuilding.
The single overhead camshaft four- and
six-cylinder engines covered in this manual
are very similar in design. Where there are
differences, they will be pointed out.
The means by which the overhead
camshaft is driven varies according to engine
type; M10 and M30 engines use a timing
chain, while M20 and M40 engines have a
timing belt.
2 Repair operations possible
with the engine in the vehicle
Many major repair operations can be
accomplished without removing the engine
from the vehicle.
Clean the engine compartment and the
exterior of the engine with some type of
degreaser before any work is done. It will
make the job easier, and help keep dirt out of
the internal areas of the engine.
Depending on the components involved, it
may be helpful to remove the bonnet to
improve access to the engine as repairs are
performed (see Chapter 11 if necessary).
Cover the wings to prevent damage to the
paint. Special pads are available, but an old
bedspread or blanket will also work.
If vacuum, exhaust, oil or coolant leaks
develop, indicating a need for gasket or seal
renewal, the repairs can generally be made
with the engine in the vehicle. The intake and
exhaust manifold gaskets, sump gasket,
crankshaft oil seals and cylinder head gasket
are all accessible with the engine in place.
Exterior components, such as the intake
and exhaust manifolds, the sump, the oil
pump, the water pump, the starter motor, the
alternator, the distributor and the fuel system
components, can be removed for repair with
the engine in place.
The cylinder head can be removed without
removing the engine, so this procedure is
covered in this Part of Chapter 2. Camshaft,
rocker arm and valve component servicing ismost easily accomplished with the cylinder
head removed; these procedures are covered
in Part B of this Chapter. Note, however, that
the camshaft on the M40 engine may be
removed with the engine in the vehicle since it
is retained by bearing caps.
In extreme cases caused by a lack of
necessary equipment, repair or renewal of
piston rings, pistons, connecting rods and
big-end bearings is possible with the engine in
the vehicle. However, this practice is not
recommended, because of the cleaning and
preparation work that must be done to the
components involved.
3 Top Dead Centre (TDC) for
No 1 piston- locating
2
Note 1:The following procedure is based on
the assumption that the distributor (if
applicable) is correctly fitted. If you are trying
to locate TDC to refit the distributor correctly,
piston position must be determined by feeling
for compression at the No 1 spark plug hole,
then aligning the ignition timing marks or
inserting the timing tool in the flywheel, as
applicable.
Note 2:The No 1 cylinder is the one closest to
the radiator.
1Top Dead Centre (TDC) is the highest point
in the cylinder that each piston reaches as it
travels up and down when the crankshaft
turns. Each piston reaches TDC on the
compression stroke and again on the exhaust
stroke, but TDC generally refers to piston
position on the compression stroke.
2Positioning the piston at TDC is an essential
part of many procedures, such as timing belt
or chain removal and distributor removal.
3Before beginning this procedure, be sure to
place the transmission in Neutral, and apply
the handbrake or chock the rear wheels. Also,
disable the ignition system by detaching the
coil wire from the centre terminal of the
distributor cap, and earthing it on the engine
block with a jumper wire. Remove the spark
plugs (see Chapter 1).
4In order to bring any piston to TDC, the
crankshaft must be turned using one of the
methods outlined below. When looking at the
front of the engine, normal crankshaft rotation
is clockwise.
(a) The preferred method is to turn the
crankshaft with a socket and ratchet
attached to the bolt threaded into the
front of the crankshaft.
(b) A remote starter switch, which may save
some time, can also be used. Follow the
instructions included with the switch.
Once the piston is close to TDC, use a
socket and ratchet as described in the
previous paragraph.
(c) If an assistant is available to turn the
ignition switch to the Start position in
short bursts, you can get the piston close
to TDC without a remote starter switch.Make sure your assistant is out of the
vehicle, away from the ignition switch,
then use a socket and ratchet as
described in (a) to complete the
procedure.
5Note the position of the terminal for the
No 1 spark plug lead on the distributor cap. If
the terminal isn’t marked, follow the plug lead
from the No 1 cylinder spark plug to the cap
(No 1 cylinder is nearest the radiator).
6Use a felt-tip pen or chalk to make a mark
directly below the No 1 terminal on the
distributor body or timing cover.
7Detach the distributor cap, and set it aside
(see Chapter 1 if necessary).
8Turn the crankshaft (see paragraph 4
above) until the timing marks (located at the
front of the engine) are aligned (see
illustration). The M40 engine does not have
any timing marks at the front of the engine,
but instead has a timing hole in the flywheel
which must be aligned with a hole in the rear
flange of the cylinder block. On this engine,
turn the crankshaft until the distributor rotor is
approaching the No 1 TDC position, then
continue to turn the crankshaft until a suitable
close-fitting drill can be inserted through the
hole in the cylinder block and into the
flywheel.
9Look at the distributor rotor - it should be
pointing directly at the mark you made on the
distributor body or timing cover.
10If the rotor is 180 degrees out, the No 1
piston is at TDC on the exhaust stroke.
11To get the piston to TDC on the
compression stroke, turn the crankshaft one
complete turn (360°) clockwise. The rotor
should now be pointing at the mark on the
distributor or timing cover. When the rotor is
pointing at the No 1 spark plug lead terminal
in the distributor cap and the ignition timing
marks are aligned, the No 1 piston is at TDC
on the compression stroke. Note:If it’s
impossible to align the ignition timing marks
when the rotor is pointing at the mark, the
timing belt or chain may have jumped the
teeth on the sprockets, or may have been
fitted incorrectly.
In-car engine repair procedures 2A•3
3.8 Align the notch in the pulley with the
notch on the timing plate, then check to
see if the distributor rotor is pointing to the
No 1 cylinder (if not, the camshaft is 180
degrees out - the crankshaft will have to
be rotated 360 degrees)
2A

8 Timing chain and
sprockets- removal,
inspection and refitting
5
Note:This procedure applies to M10 and M30
engines.
Caution: Once the engine is set
at TDC, do not rotate the
camshaft or crankshaft until the
timing chain is reinstalled. If the
crankshaft or camshaft is rotated with the
timing chain removed, the valves could hit
the pistons, causing expensive internal
engine damage.
Removal
1Position the No 1 cylinder at Top Dead
Centre (TDC) on the compression stroke (see
Section 3).
2Remove the valve cover (see Section 4).
Double-check that the No 1 cylinder is at TDC
on the compression stroke by making sure the
No 1 cylinder rocker arms are loose (not
compressing their valve springs).
3Remove the upper timing chain cover (see
Section 7). Note the location of the camshaft
timing marks, which should now be aligned.
On four-cylinder (M10) engines, there’s
usually a stamped line on the camshaft flange
that aligns with a cast mark on the top of the
cylinder head; also, the camshaft sprocket
dowel pin hole will be at its lowest point. On
six-cylinder (M30) engines, a line drawn
through two of the camshaft sprocket bolts
opposite each other would be exactly vertical,
while a line drawn through the other two bolts
would be horizontal. Additionally, the locating
pin should be in the lower left corner (between
the 7 and 8 o’clock positions). Be sure you’ve
identified the correct camshaft TDC position
before dismantling, because correct valve
timing depends on you aligning them exactly
on reassembly. Note:As the engine is
mounted in the engine compartment at anangle, all references to horizontal and vertical
whilst timing the camshafts are in relation to
the crankshaft, and not the ground.
4Hold the crankshaft stationary with a socket
and ratchet on the vibration damper centre bolt,
then loosen (but don’t unscrew completely) the
four bolts attaching the camshaft sprocket to
the camshaft. Be very careful not to rotate the
camshaft or crankshaft. Note:Some earlier
models may have locking tabs for the camshaft
sprocket bolts. Bend the tabs down before
loosening the bolts. The tabs are no longer
available from the manufacturer, and do not
have to be used on refitting.
5Remove the lower timing chain cover (see
Section 7).
6Unscrew and remove the four camshaft
sprocket bolts, then disengage the chain from
the crankshaft sprocket and carefully remove
the chain and camshaft sprocket from the
engine. It may be necessary to gently prise
the camshaft sprocket loose from the
camshaft with a screwdriver.
Inspection
Timing sprockets
7Examine the teeth on both the crankshaft
sprocket and the camshaft sprocket for wear.
Each tooth forms an inverted V. If worn, the
side of each tooth under tension will be
slightly concave in shape when compared
with the other side of the tooth (i.e. one side of
the inverted V will be concave when
compared with the other, giving the teeth a
hooked appearance). If the teeth appear to be
worn, the sprockets must be renewed. Note:
The crankshaft sprocket is a press fit on the
crankshaft, and can be removed with a jaw-
type puller after the Woodruff key and oil
pump are removed (see Section 14). However,
BMW recommends the new sprocket be
pressed onto the crankshaft after being
heated to 80°C (175°F) on the M10 engine, or
to 200°C(390°F) on the M30 engine. For this
reason, if the crankshaft sprocket requires
renewal, we recommend removing the
crankshaft (see Part B of this Chapter) and
taking it to an engineering works to have the
old sprocket pressed off and a new one
pressed on.
Timing chain
8The chain should be renewed if the
sprockets are worn or if the chain is loose
(indicated by excessive noise in operation).
It’s a good idea to renew the chain anyway if
the engine is stripped down for overhaul. The
rollers on a very badly worn chain may be
slightly grooved. To avoid future problems, if
there’s any doubt at all about the chain’s
condition, renew it.
Chain rail and tensioner
9Inspect the chain guide rail and tensioner
rail for deep grooves caused by chain contact.
Renew them if they are excessively worn. The
rails can be renewed after removing the
circlips with a pointed tool or needle-nose
pliers (see illustration).10Shake the tensioner plunger, and listen for
a rattling sound from the check ball. If you
can’t hear the ball rattling, renew the plunger.
11To further check the tensioner plunger,
blow through it first from the closed end, then
from the slotted (guide) end. No air should
flow through the plunger when you blow
through the closed end, and air should flow
through it freely when you blow through the
slotted end. If the tensioner fails either test,
renew it.
Refitting
12Refit the tensioner rail and chain guide
rail, if removed.
13Temporarily refit the lower timing chain
cover and vibration damper, so you can check
the crankshaft timing marks. Once you’ve
verified the TDC marks are aligned, remove
the damper and cover.
14Loop the timing chain over the crankshaft
sprocket, then loop it over the camshaft
sprocket and, guiding the chain between the
chain guide and tensioner rail, refit the
camshaft sprocket on the camshaft. Make
sure the camshaft timing marks are aligned.
15The remainder of refitting is the reverse of
removal. Be sure to tighten the fasteners to
the correct torques (see this Chapter’s Speci-
fications).
9 Timing belt covers-
removal and refitting
2
Note:This procedure applies to M20 and M40
engines.
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.
2Remove the fan clutch and fan shroud (see
Chapter 3).
3On the M20 engine, remove the radiator
(see Chapter 3).
4Remove the fan drivebelt pulley.
2A•8 In-car engine repair procedures
9.6a Unbolt the distributor cap
(M40 engine) . . .
8.9 To remove the tensioner or chain guide
rail, remove the circlips with a pointed tool
or needle-nose pliers - the circlips tend to
fly off when they’re released, so make sure
you catch them or they’ll get lost (or,
worse, wind up in the engine!)

alignment mark on the camshaft sprocket and
rear timing cover to ensure correct refitting.
6On the M20 engine, loosen the two
tensioner roller retaining bolts a little, and
push the tensioner towards the water pump
(see illustration). With the timing belt tension
relieved, re-tighten the retaining bolt.
7On the M40 engine, loosen the tensioner
retaining nut, and use an Allen key to rotate
the tensioner clockwise. This will relieve the
tension of the timing belt. Tighten the
retaining nut to hold the tensioner in its free
position.
8If the same belt is to be refitted, mark it with
an arrow indicating direction of rotation.
Caution: It is not advisable to
refit a timing belt which has been
removed unless it is virtually
new. On the M40 engine, BMW
recommend that the timing belt is
renewed every time the tensioner roller is
released.
9Remove the timing belt by slipping it off the
roller(s) and the other sprockets (see
illustrations).
10If it’s necessary to remove the camshaft
or the intermediate shaft sprocket, remove the
sprocket bolt while holding the sprocket to
prevent it from moving. To hold the sprocket,
wrap it with a piece of an old timing belt
(toothed side engaging the sprocket teeth) ora piece of leather, then hold the sprocket
using a strap spanner. If a strap spanner is not
available, clamp the ends of the piece of belt
or leather tightly together with a pair of grips.
Before loosening the bolt, make sure you have
the necessary tool for positioning the
camshaft as described in the following
paragraph (see illustration).
Caution: Do not use the timing
belt you’re planning to refit to
hold the sprocket. Also, be sure
to hold the camshaft sprocket
very steady, because if it moves more than
a few degrees, the valves could hit the
pistons.
Note: On the M40 engine, the sprocket is not
directly located on the camshaft with a key, as
the groove in the end of the camshaft allows
the sprocket to move several degrees in either
direction. The retaining bolt locks the sprocket
onto a taper after positioning the camshaft
with a special tool.
11The BMW tool for positioning the camshaft
on the M40 engine consists of a metal plate
which locates over the square lug near the No
1 cylinder lobes on the camshaft - the valve
cover must be removed first (see
illustrations). If the BMW tool cannot be
obtained, a home-made tool should be
fabricated out of metal plate. The tool must be
made to hold the square lug on the camshaft
at right-angles to the upper face of the cylinder
head (ie the contact face of the valve cover).
12If it’s necessary to remove the crankshaft
sprocket, remove the crankshaft hub centre
bolt while holding the crankshaft steady.
Note:The removal of the crankshaft hub
mounting bolt requires a heavy-duty holding
device because of the high torque used to
tighten the bolt. BMW has a special tool,
numbered 112150 (M20 engines) or 112170
(M40 engines), for this purpose. If this tool
cannot be bought or borrowed, check with a
tool dealer or motor factors for a tool capable
of doing the job. Note that the tool number
112170 bolts on the rear of the cylinder head
and engages with the flywheel ring gear, so it
will only be possible to use this tool if the
gearbox has been removed, or if the engine is
out of the vehicle (see illustrations). On
2A•10 In-car engine repair procedures
10.12a Home-made tool for holding the
crankshaft stationary while the crankshaft
pulley bolt is being loosened (engine
removed for clarity)
10.11b The BMW camshaft-holding tool in
position on the M40 engine10.11a The BMW tool for holding the
camshaft in the TDC position on
M40 engines
10.10 Removing the camshaft sprocket on
the M40 engine
10.9b Removing the timing belt from the
camshaft sprocket on the M40 engine
10.9a When removing the timing belt on
models with a two-piece crankshaft hub,
it’s a tight fit to remove it around the hub,
but it’s a lot easier than removing the
crankshaft hub assembly, which is secured
by a very tight bolt10.6 Loosen the idler pulley bolts
(arrowed) to relieve the tension on the
timing belt so it can be removed

models with a two-piece hub, after removing
the outer hub piece, you’ll then need to
remove the sprocket with a bolt-type puller
(available at most motor factors). When using
the puller, thread the crankshaft centre bolt in
approximately three turns, and use this as a
bearing point for the puller’s centre bolt.
Inspection
13Check for a cracked, worn or damaged
belt. Renew it if any of these conditions are
found (see illustrations). Also look at the
sprockets for any signs of irregular wear or
damage, indicating the need for renewal.
Note:If any parts are to be renewed, check
with your local BMW dealer parts department
to be sure compatible parts are used. On M20
engines, later sprockets, tensioner rollers and
timing belts are marked “Z 127”. Renewal of
the timing belt on M20 engines will mean that
the later belt tensioner should also be fitted, if
not already done.
14Inspect the idler roller and, on M20
engines, the tension spring. Rotate the
tensioner roller to be sure it rotates freely, with
no noise or play. Note:When fitting a new
timing belt, it is recommended that a new
tensioner be fitted also.
Refitting
15On the M20 engine, refit the idler/
tensioner/spring so that the timing belt can be
fitted loosely.
16Refit the sprockets using a reversal of the
removal procedure; tighten the retaining bolts
to the specified torque. On the M40 engine,
turn the camshaft sprocket clockwise as far
as possible within the location groove, then
tighten the retaining bolt to an initial torque of
1 to 3 Nm at this stage.
17If you are refitting the old belt, make sure
the mark made to indicate belt direction of
rotation is pointing the right way (the belt
should rotate in a clockwise direction as you
face the front of the engine).
18Refit the timing belt, placing the belt
under the crankshaft sprocket first to get bythe housing. Guide the belt around the other
sprocket(s).
19Finally, place the belt over the
idler/tensioner rollers.
20On the M20 engine, loosen the tensioner
bolts and allow the spring tension to be
applied to the belt.
21On the M20 engine, lightly apply pressure
behind the tensioner to be sure spring
pressure is being applied to the belt (see
illustration). Don’t tighten the bolts while
applying pressure; lightly tighten the bolts
only after releasing the tensioner.
22On the M40 engine, unbolt and remove
the valve cover, then use the special tool to
hold the camshaft in the TDC position (see
paragraph 11).
23On the M40 engine, loosen the tensioner
roller retaining nut, and use an Allen key to
rotate the roller anti-clockwise until the timing
belt is tensioned correctly. The 90°-twist
method of checking the tension of the timing
belt is not accurate enough for this engine,
and it is strongly recommended that the
special BMW tensioning tool is obtained if at
all possible (apply 32 ±2 graduations on the
tool) (see illustration). A reasonably accurate
alternative can be made using an Allen key
and a spring balance (see illustration).Make
sure that the spring balance is positioned as
shown, since the tensioner roller is on an
eccentric, and different readings will be
obtained otherwise. The spring balance
should be connected 85 mm along the Allen
key, and a force of 2.0 kg (4.4 lb) should be
In-car engine repair procedures 2A•11
10.13a Inspect the timing belt carefully for
cracking, as shown here. . .
10.13b . . . and any other damage
10.12c Removing the crankshaft sprocket
from the front of the crankshaft10.12b Removing the crankshaft pulley
bolt (M40 engine)
10.23b Using a spring balance and Allen
key to adjust the tension of the timing belt
on the M40 engine
Dimension A = 85 mm
10.23a Using the special BMW tool to
check the tension of the timing belt on the
M40 engine
10.21 On the M20 engine, after the belt
has been installed correctly around all
sprockets and the tensioner pulley, lightly
apply pressure to the tensioner, to be sure
the tensioner isn’t stuck and has full
movement against the timing belt
2A