1985 BMW 3 SERIES section 17

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 Introduction
This Chapter is designed to help the home
mechanic maintain his or her vehicle with the
goals of maximum performance, economy,
safety and reliability in mind. Included is a
master maintenance schedule, followed by
procedures dealing specifically with each item
on the schedule. Visual checks, adjustments,
component renewal and other helpful items
are included. Refer to the accompanying
illustrations of the engine compartment and
the underside of the vehicle for the locations
of various components. Servicing the vehicle,
in accordance with the mileage/time
maintenance schedule and the step-by-step
procedures, will result in a planned
maintenance programme that should produce
a long and reliable service life. Keep in mind
that it is a comprehensive plan, so maintaining
some items but not others at specified
intervals, will not produce the same results.
2 Routine maintenance
As you service the vehicle, you will discover
that many of the procedures can - and should
- be grouped together, because of the nature
of the particular procedure you’re performing,
or because of the close proximity of two
otherwise-unrelated components to one
another. For example, if the vehicle is raised
for chassis lubrication, you should inspect the
exhaust, suspension, steering and fuelsystems while you’re under the vehicle. When
the wheels are removed for other work, it
makes good sense to check the brakes, since
the wheels are already removed. Finally, let’s
suppose you have to borrow a torque wrench.
Even if you only need it to tighten the spark
plugs, you might as well check the torque of
as many critical nuts and bolts as time allows.
The first step in this maintenance
programme is to prepare yourself before the
actual work begins. Read through all the
procedures you’re planning to do, then gather
up all the parts and tools needed. If it looks
like you might run into problems during a
particular job, seek advice from a mechanic or
an experienced do-it-yourselfer.
3 Engine “tune-up”-
general information
The term “tune-up” is used in this manual to
represent a combination of individual
operations rather than one specific procedure.
If, from the time the vehicle is new, the
routine maintenance schedule is followed
closely, and frequent checks are made of fluid
levels and high-wear items, as suggested
throughout this manual, the engine will be
kept in relatively good running condition, and
the need for additional work will be minimised.
More likely than not, however, there will be
times when the engine is running poorly due
to a lack of regular maintenance. This is even
more likely if a used vehicle, which has not
received regular and frequent maintenance
checks, is purchased. In such cases, an
engine tune-up will be needed outside of the
regular maintenance intervals. The first step in any tune-up or diagnostic
procedure to help correct a poor-running
engine is a cylinder compression check. A
compression check (see Chapter 2B) will help
determine the condition of internal engine
components, and should be used as a guide
for tune-up and repair procedures. If, for
instance, a compression check indicates
serious internal engine wear, a conventional
tune-up will not improve the performance of
the engine, and would be a waste of time and
money. Because of its importance, the
compression check should be done by
someone with the right equipment, and the
knowledge to use it properly.
The following procedures are those most
often needed to bring a generally poor-
running engine back into a proper state of
tune.
Minor tune-up
Check all engine-related fluids (Section 4)
Check all underbonnet hoses (Section 10)
Check and adjust the drivebelts (Sec-
tion 11)
Clean, inspect and test the battery (Sec-
tion 13)
Renew the spark plugs (Section 14)
Inspect the spark plug HT leads, distributor
cap and rotor (Section 15)
Check the air filter (Section 20)
Check the cooling system (Section 22)
Major tune-up
All items listed under minor tune-up, plus . . .
Check the ignition system (see Chapter 5)
Check the charging system (see Chapter 5)
Check the fuel system (see Chapter 4)
Renew the spark plug HT leads, distributor
cap and rotor (Section 15)
1•7
1
Routine Maintenance
Weekly checks
4 Fluid level checks
1
Note:The following are fluid level checks to
be done on a 250-mile or weekly basis.
Additional fluid level checks can be found in
specific maintenance procedures which
follow. Regardless of intervals, be alert to fluid
leaks under the vehicle, which would indicate
a fault to be corrected immediately.
1Fluids are an essential part of the
lubrication, cooling, brake and windscreen
washer systems. Because the fluids gradually
become depleted and/or contaminated during
normal operation of the vehicle, they must be
periodically replenished. See “Lubricants and
fluids”at the beginning of this Chapter before
adding fluid to any of the following
components. Note:The vehicle must be on
level ground when any fluid levels are
checked.
Engine oil
2Engine oil is checked with a dipstick, which
is located on the side of the engine (refer to
the underbonnet illustrations in this Chapter
for dipstick location). The dipstick extends
through a metal tube down into the sump.
3The engine oil should be checked before
the vehicle has been driven, or at least
15 minutes after the engine has been shut off.
4Pull the dipstick out of the tube, and wipe
all of the oil away from the end with a clean
rag or paper towel. Insert the clean dipstick all
the way back into the tube, and pull it out
again. Note the oil at the end of the dipstick.
At its highest point, the oil should be betweenthe two notches or marks (see illustration).
5It takes one litre of oil to raise the level from
the lower mark to the upper mark on the
dipstick. Do not allow the level to drop below
the lower mark, or oil starvation may cause
4.4 The oil level should be kept between
the two marks, preferably at or near the
upper one - if it isn’t, add enough oil to
bring the level to the upper mark
If the oil is checked
immediately after driving the
vehicle, some of the oil will
remain in the upper part of
the engine, resulting in an inaccurate
reading on the dipstick.

engine damage. Conversely, overfilling the
engine (adding oil above the upper mark) may
cause oil-fouled spark plugs, oil leaks, or oil
seal failures.
6To add oil, remove the filler cap located on
the valve cover (see illustrations). After
adding oil, wait a few minutes to allow the
level to stabilise, then pull the dipstick out and
check the level again. Add more oil if required.
Refit the filler cap, tightening it by hand only.
7Checking the oil level is an important
preventive maintenance step. A consistently
low oil level indicates oil leakage through
damaged seals or defective gaskets, or oil
burning (internal leakage past worn rings or
valve guides). The condition of the oil should
also be noted. If the oil looks milky in colour or
has water droplets in it, the cylinder head
gasket may be blown, or the head or block
may be cracked. The engine should be
repaired immediately. Whenever you check
the oil level, slide your thumb and index finger
up the dipstick before wiping off the oil. If you
see small dirt or metal particles clinging to the
dipstick, the oil should be changed (see
Section 6).
Engine coolant
Warning: Do not allow antifreeze
to come in contact with your
skin, or with the vehiclepaintwork. 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.
8All vehicles covered by this manual are
equipped with a pressurised coolant recovery
system. On most models, a white plastic
expansion tank (or coolant reservoir) located
in the engine compartment is connected by a
hose to the radiator. As the engine heats up
during operation, the expanding coolant fills
the tank. As the engine cools, the coolant is
automatically drawn back into the cooling
system, to maintain the correct level.
9The coolant level in the reservoir (see
illustrations)should be checked regularly.
Add a 40%/60% mixture of ethylene glycol-
based antifreeze to water (see illustration).
Warning: Do not remove the
expansion tank cap or radiator
cap to check the coolant level,
unless the engine is completely
cold! The level in the reservoir varies with
the temperature of the engine. When the
engine is cold, the coolant level should beabove the LOW mark on the reservoir.
Once the engine has warmed up, the level
should be at or near the FULL mark. If it
isn’t, allow the engine to cool, then remove
the cap from the reservoir.
10Drive the vehicle and recheck the coolant
level. If only a small amount of coolant is
required to bring the system up to the proper
level, plain water can be used. However,
repeated additions of water will dilute the
antifreeze. In order to maintain the proper
ratio of antifreeze and water, always top-up
the coolant level with the correct mixture.
11If the coolant level drops consistently,
there must be a leak in the system. Inspect
the radiator, hoses, filler cap, drain plugs and
water pump (see Section 29). If no leaks are
noted, have the expansion tank cap or
radiator cap pressure-tested by a BMW
dealer.
12If you have to remove the cap, wait until
the engine has cooled completely, then wrap
a thick cloth around the cap and turn it to the
first stop. If coolant or steam escapes, let the
engine cool down longer, then remove the
cap.
13Check the condition of the coolant as
well. It should be relatively clear. If it’s brown
or rust-coloured, the system should be
drained, flushed and refilled. Even if the
coolant appears to be normal, the corrosion
1•8
4.9d Adding antifreeze mixture4.9c On some 5-Series models, the
expansion tank (coolant reservoir) is
located on the bulkhead4.9b On other models, the expansion tank
(coolant reservoir) is located on the side of
the engine compartment - remove the cap
to add coolant
4.9a On some models, the expansion tank
(coolant reservoir) is mounted on the
radiator - make sure the level is kept at or
near the FULL mark (arrowed)4.6b Topping-up the engine oil4.6a The threaded oil filler cap is located
in the valve cover - always make sure the
area around the opening is clean before
unscrewing the cap
Weekly Checks

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.

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

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

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.