Oil BMW 3 SERIES 1991 E30 Workshop Manual

0•4Introduction
The E30 3-Series range first became
available in the UK in March 1983, and
continued in production until April 1991, when
the revised E36 3-Series range (not covered
by this manual) was introduced. Convertible
and Touring (Estate) models were introduced
for 1988, and these models have continued in
E30 form to date.
The E28 5-Series models were introduced
in October 1981, and were superseded in
June 1988 by the revised E34 5-Series range,
Touring versions of which became available
from March 1992. Throughout this manual,
E28 models are also referred to as “old-
shape”, while E34 models are designated
“new-shape”.
The models covered by this manual are
equipped with single overhead cam in-line
four- and six-cylinder engines. Early 316 and
518 models are fitted with carburettors, but all
other models are fitted with fuel injection
systems. Transmissions are a five-speed
manual, or three- or four-speed automatic.
The transmission is mounted to the back of
the engine, and power is transmitted to the
fully-independent rear axle through a two-
piece propeller shaft. The final drive unit is
bolted solidly to a frame crossmember, and
drives the rear wheels through driveshaftsequipped with inner and outer constant
velocity joints.
The front suspension is of MacPherson
strut type, with the coil spring/shock absorber
unit making up the upper suspension link. The
rear suspension is made up of coil spring-
over-shock absorber struts, or coil springs
and conventional shock absorbers,
depending on model.
The brakes are disc type at the front, with
either drums or discs at the rear, depending
on model. Servo assistance is standard on all
models. Some later models are equipped with
an Anti-lock Braking System (ABS).
All models are manufactured to fine limits,
and live up to the BMW reputation of quality
workmanship. Although many of the models
covered by this manual appear complex at
first sight, they should present no problems to
the home mechanic.
Note for UK readers
The greater part of this manual was
originally written in the USA. Some of the
photographs used are of American-market
models, but the procedures given are fully
applicable to right-hand-drive models (or have
been amended where necessary).
Acknowledgements
Thanks are due to Champion Spark Plug,
who supplied the illustrations showing spark
plug conditions. Thanks are also due to
Sykes-Pickavant Limited, who provided some
of the workshop tools, and to all those people
at Sparkford who helped in the production of
this manual. Technical writers who
contributed to this project include Robert
Maddox, Mark Ryan and Mike Stubblefield.
We take great pride in the accuracy of
information given in this manual, but
vehicle manufacturers make alterations
and design changes during the production
run of a particular vehicle of which they do
not inform us. No liability can be accepted
by the authors or publishers for loss,
damage or injury caused by any
errors in, or omissions from, the
information given.
Project vehicles
The main project vehicle used in the
preparation of this manual for the UK market
was a 1988 BMW 318i with an M40/B18
engine.
Introduction to the BMW 3- and 5-Series
BMW 320i Saloon (E30)

0•6Safety First!
Working on your car can be dangerous.
This page shows just some of the potential
risks and hazards, with the aim of creating a
safety-conscious attitude.
General hazards
Scalding
• Don’t remove the radiator or expansion
tank cap while the engine is hot.
• Engine oil, automatic transmission fluid or
power steering fluid may also be dangerously
hot if the engine has recently been running.
Burning
• Beware of burns from the exhaust system
and from any part of the engine. Brake discs
and drums can also be extremely hot
immediately after use.
Crushing
• When working under or near
a raised vehicle,
always
supplement the
jack with axle
stands, or use
drive-on
ramps.
Never
venture
under a car which
is only supported by a jack.
• Take care if loosening or tightening high-
torque nuts when the vehicle is on stands.
Initial loosening and final tightening should
be done with the wheels on the ground.
Fire
• Fuel is highly flammable; fuel vapour is
explosive.
• Don’t let fuel spill onto a hot engine.
• Do not smoke or allow naked lights
(including pilot lights) anywhere near a
vehicle being worked on. Also beware of
creating sparks
(electrically or by use of tools).
• Fuel vapour is heavier than air, so don’t
work on the fuel system with the vehicle over
an inspection pit.
• Another cause of fire is an electrical
overload or short-circuit. Take care when
repairing or modifying the vehicle wiring.
• Keep a fire extinguisher handy, of a type
suitable for use on fuel and electrical fires.
Electric shock
• Ignition HT
voltage can be
dangerous,
especially to
people with heart
problems or a
pacemaker. Don’t
work on or near the
ignition system with
the engine running or
the ignition switched on.• Mains voltage is also dangerous. Make
sure that any mains-operated equipment is
correctly earthed. Mains power points should
be protected by a residual current device
(RCD) circuit breaker.
Fume or gas intoxication
• Exhaust fumes are
poisonous; they often
contain carbon
monoxide, which is
rapidly fatal if inhaled.
Never run the
engine in a
confined space
such as a garage
with the doors shut.
• Fuel vapour is also
poisonous, as are the vapours from some
cleaning solvents and paint thinners.
Poisonous or irritant substances
• Avoid skin contact with battery acid and
with any fuel, fluid or lubricant, especially
antifreeze, brake hydraulic fluid and Diesel
fuel. Don’t syphon them by mouth. If such a
substance is swallowed or gets into the eyes,
seek medical advice.
• Prolonged contact with used engine oil can
cause skin cancer. Wear gloves or use a
barrier cream if necessary. Change out of oil-
soaked clothes and do not keep oily rags in
your pocket.
• Air conditioning refrigerant forms a
poisonous gas if exposed to a naked flame
(including a cigarette). It can also cause skin
burns on contact.
Asbestos
• Asbestos dust can cause cancer if inhaled
or swallowed. Asbestos may be found in
gaskets and in brake and clutch linings.
When dealing with such components it is
safest to assume that they contain asbestos.
Special hazards
Hydrofluoric acid
• This extremely corrosive acid is formed
when certain types of synthetic rubber, found
in some O-rings, oil seals, fuel hoses etc, are
exposed to temperatures above 400
0C. The
rubber changes into a charred or sticky
substance containing the acid. Once formed,
the acid remains dangerous for years. If it
gets onto the skin, it may be necessary to
amputate the limb concerned.
• When dealing with a vehicle which has
suffered a fire, or with components salvaged
from such a vehicle, wear protective gloves
and discard them after use.
The battery
• Batteries contain sulphuric acid, which
attacks clothing, eyes and skin. Take care
when topping-up or carrying the battery.
• The hydrogen gas given off by the battery
is highly explosive. Never cause a spark or
allow a naked light nearby. Be careful when
connecting and disconnecting battery
chargers or jump leads.
Air bags
• Air bags can cause injury if they go off
accidentally. Take care when removing the
steering wheel and/or facia. Special storage
instructions may apply.
Diesel injection equipment
• Diesel injection pumps supply fuel at very
high pressure. Take care when working on
the fuel injectors and fuel pipes.
Warning: Never expose the hands,
face or any other part of the body
to injector spray; the fuel can
penetrate the skin with potentially fatal
results.
Remember...
DO
• Do use eye protection when using power
tools, and when working under the vehicle.
• Do wear gloves or use barrier cream to
protect your hands when necessary.
• Do get someone to check periodically
that all is well when working alone on the
vehicle.
• Do keep loose clothing and long hair well
out of the way of moving mechanical parts.
• Do remove rings, wristwatch etc, before
working on the vehicle – especially the
electrical system.
• Do ensure that any lifting or jacking
equipment has a safe working load rating
adequate for the job.
A few tips
DON’T
• Don’t attempt to lift a heavy component
which may be beyond your capability – get
assistance.
• Don’t rush to finish a job, or take
unverified short cuts.
• Don’t use ill-fitting tools which may slip
and cause injury.
• Don’t leave tools or parts lying around
where someone can trip over them. Mop
up oil and fuel spills at once.
• Don’t allow children or pets to play in or
near a vehicle being worked on.

0•10Roadside Repairs
Puddles on the garage floor or drive, or
obvious wetness under the bonnet or
underneath the car, suggest a leak that needs
investigating. It can sometimes be difficult to
decide where the leak is coming from,
especially if the engine bay is very dirty
already. Leaking oil or fluid can also be blown
rearwards by the passage of air under the car,
giving a false impression of where the
problem lies.Warning: Most automotive oils
and fluids are poisonous. Wash
them off skin, and change out of
contaminated clothing, without
delay.
Identifying leaks
The smell of a fluid leaking
from the car may provide a
clue to what’s leaking. Some
fluids are distinctively
coloured. It may help to clean the car
carefully and to park it over some clean
paper overnight as an aid to locating the
source of the leak.
Remember that some leaks may only
occur while the engine is running.
Sump oil Gearbox oil
Brake fluid Power steering fluidOil from filter
Antifreeze
Engine oil may leak from the drain plug......or from the base of the oil filter.
Leaking antifreeze often leaves a crystalline
deposit like this.Gearbox oil can leak from the seals at the
inboard ends of the driveshafts.
A leak occurring at a wheel is almost
certainly brake fluid.Power steering fluid may leak from the pipe
connectors on the steering rack.

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

Tyre pressures (cold) - bars (psi)Front Rear
3-Series, E30
316 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 (28) 2.1 (30)
316i
Saloon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.1 (30)
Estate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.2 (32)
318i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 (26) 1.9 (28)
320i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 (28) 2.0 (29)
325i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 (32) 2.3 (33)
5-Series, E28 (“old-shape”)
518 and 518i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.0 (29)
525i and 528i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 (32) 2.2 (32)
535i and M535i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 (33) 2.5 (36)
5-Series, E34 (“new-shape”)
518i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.0 (29)
520i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 (32) 2.1 (30)
525i, 530i and 535i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.3 (33)
Torque wrench settingsNm
Automatic transmission sump bolts
Three-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 to 9
Four-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 to 7
Spark plugs
M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 to 30
Except M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 33
Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 33
Wheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Lubricants and fluids
Component or system Lubricant type/specification
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multigrade engine oil, viscositySAE 10W/40 to 20W/50, to API SG
Cooling system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ethylene glycol-based antifreeze with corrosion inhibitors
Manual transmission* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gear oil, viscosity SAE 80 to API-GL4, or single-grade mineral-based
engine oil, viscosity SAE 20, 30 or 40 to API-SG
Automatic transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dexron ll type ATF
Final drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BMW-approved hypoid gear oil, viscosity SAE 90**
Brake and clutch hydraulic systems . . . . . . . . . . . . . . . . . . . . . . . . . . Hydraulic brake fluid to SAE J 1703 or DOT 4
Power steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dexron ll type ATF
* E34 520i & 525i with air conditioning, E34 530i & 535i - Dexron II type ATF)
** Only available in bulk; refer to your BMW dealer
Capacities*
1•3
1
Engine oil
M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 litres
M20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 litres
M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.8 litres
M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 litres
Cooling system
M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 litres
M20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 litres
M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.0 litres
M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 litres
Fuel tank
3-Series, E30
Saloon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 litres (early),
64 litres (later)
Estate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 litres (early),
70 litres (later)
5-Series
E28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . 70 litres
E34 (“new-shape”) . . . . . . . . . . . . . . . . . . . . . . . 81 litresManual transmission
ZF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 litres
Getrag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 to 1.5 litres
Automatic transmission (refill)
3-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 litres
4-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 litres
Final drive capacity (drain and refill)
3-Series, E30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.9 litres
5-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . 0.9 litres
5-Series, E34 (“new-shape”) . . . . . . . . . . . . . . . . . 1.7 litres
*All capacities approximate
Servicing Specifications

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

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

1•6Maintenance and Servicing
Front underbody view of a UK model 318i
(1988)
1 Radiator
2 Engine oil drain plug
3 Front suspension control arm (left-hand
side)
4 Front anti-roll bar
5 Clutch slave cylinder
6 Transmission
7 Exhaust downpipe
8 Front suspension control arm (right-hand
side)
Typical rear underside components
1 Exhaust system
2 Differential fill/check plug
3 Driveshaft boot
4 Fuel tank filler tube
5 Differential drain plug
6 Rear brake
7 Rear shock absorber

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