engine coolant FIAT UNO 1983 Service Manual PDF

14•20 Wiring diagrams
Component key for wiring diagrams 30 to 52
Note: Not all the items listed will be fitted to all models
No Description
1 Injector cooling fan
2 Left front light cluster
3 Left foglamp
4 Left front engine compartment earth
5 Radiator cooling fan
6 Double contact thermostatic switch
on engine radiator
6A Thermostatic switch on engine
radiator
7 Left horn
8 Right horn
9 Resistor for engaging radiator fan 1st
speed
10 Right front light cluster
11 Right foglamp
12 Right front engine compartment earth
13 Battery
14 Ignition coil
15 Ignition distributor with magnetic
impulse generator
16 Left front side direction indicator
17 Ignition power module
18 MPi electronic injection control unit
19 Join between injection/ignition cables
in engine compartment
20 Battery cables join in engine
compartment
21 Antiskid braking system wiring join
22 Starting go-ahead relay
23 Earth for battery
24 Radiator coolant temperature sender
unit for electronic injection
25 Anti-knock sensor
26 Injection system diagnostic socket
27 Switch signalling insufficient engine
oil pressure
28 Radiator coolant temperature sender
unit
29 Engine oil temperature sender unit
30 Engine oil pressure sender unit
31 Right front side direction indicator
32 Engine oil temperature sender unit
cable join
33 Battery recharging signal cable join
34 Windscreen washer pump
35 Rear screen washer pump
36 Reversing switch
37 Fuel injectors relay feed
38 Insufficient brake fluid level sensor
39 Left brake pad wear sensor
40 Microplex electronic ignition control
unit
41 Injection cables join in engine
compartment
42 Ignition cables join in engine
compartment
43 Join between battery cable and
injection cables
44 Join between engine cable and
battery cables
45 Left front brake pad cables join
46 Starter motorNo Description
47 Windscreen wiper motor
48 Headlamp washer pump
49 Fuel injector
50 Fuel injector
51 Fuel injector
52 Fuel injector
53 Supplementary air valve
54 Spark plug
55 Spark plug
56 Spark plug
57 Spark plug
58 Excess supercharging pressure
switch
59 Throttle position switch
60 Engine speed sensor
61 Ignition diagnostic socket
62 Connector block
63 Connector block
64 Alternator
65 Thermostatic switch for injector
cooling fan
66 Right brake pad wear sensor
67 TDC sensor
68 Connector block
69 Connector block
70 Connector block
71 Connector block
72 Join with right brake pad cables
73 Electronic earth
74 Power earth
75 Brake stop-lamp switch
76 20 A fuse for central locking
77 10 A fuse for electric fuel pump
78 30 A fuse for radiator cooling fan
79 30 A fuse for electric windows
80 10 A fuse for injector cooling fan
81 20 A fuse for headlamp
wash/wipe
82 20 A fuse for foglamps
83 Junction box with fuses and relays:
E1 Horn relay (for single tone horns
bridge between 86 and 87)
E2 Heated rear screen relay
E3 Heater (bridge between 85 and 30)
84 Join between front cable and rear
cables
85 Join between front cable and door
ajar sensor cables
86 Earth on dashboard, left hand side
87 Earth on dashboard, right hand
side
88 Choke warning light switch
89 Ignition switch
90 Hazard warning lights switch
91 Steering column switch unit
A Rear screen wash/wipe switch
B Horn button
C Direction indicators switch
D Windscreen wiper intermittent
speed selector switch
E Windscreen/headlamp washer
control switchNo Description
F Rear foglamps/headlamp washer
intermittent device switch
G Headlamp dip switch
H External lights switch
I Flasher switch
92 Foglamp relay
93 Electric fuel pump relay
94 Electric windows relay feed
95 Headlamp wash/wipe intermittent
device
96 Direction indicators/hazard warning
lights flasher unit
97 Central locking receiver
98 Central locking control unit
99 Join with brake pad cables
100 Join between engine cable and
dashboard cables
101 Automatic heater cable join
102 Instrument panel
A Foglamps warning light
B Main beam headlamps warning
light
C Side lights warning light
D Rear foglamps warning light
E Heated rear screen warning light
F Hazard warning lights warning
light
G Direction indicators warning light
H Handbrake applied and insufficient
brake fluid level warning light
I Choke warning light
K Instrument panel light bulbs
L Battery recharging warning light
M Insufficient engine oil pressure
warning light
O Antiskid braking system failure
warning light
P Maximum turbocharging pressure
warning light
Q Brake pad wear warning light
R Door ajar warning light
U Fuel level gauge
V Engine oil pressure gauge
W Engine oil temperature gauge
Y Tachometer
Z Coolant temperature gauge
103 Join with remote control central
locking cables
104 Cigar lighter
105 Radio receiver
106 Heater unit
107 Switch unit
A Heated rear screen switch
B Rear foglamps switch
C Switch unit light bulb
D Rear screen wiper switch
E Foglamps switch
F Clock
108 Left front electric window motor
109 Left front central locking geared
motor
110 Switch signalling left front door ajar

Wiring diagrams 14•21
14
Component key for wiring diagrams 30 to 52 (continued)
Note: Not all the items listed will be fitted to all models
No Description
111 Push button on left front pillar for
centre courtesy light
112 Front electric windows switch panel,
driver’s side
113 Join between dashboard cable and
adjustable map reading light cables
114 Join with left front electric window
cables
115 Join between dashboard cable and
rear cables
116 Join between rear cable and courtesy
light cables
117 Left front speaker
118 Handbrake ‘on’ switch
119 Centre courtesy light bulb
119A Adjustable map reading light on rear
view mirror
120 Right front electric window motor
121 Right front central locking geared
motor
122 Switch signalling right front door ajar
123 Push button on right front pillar for
centre courtesy light
124 Electric windows control panel,
passenger side
125 Fuel level gauge
126 Join with right front electric window
cables
127 Join between engine cable and
dashboard cables
128 Right front speaker
129 Left rear light cluster
130 Join between rear cable and luggage
compartment courtesy light
131 Windscreen washer pump wiring join
132 Rear screen washer pump wiring join
133 Left rear earth
134 Rear screen wiper motor
135 Electric fuel pump
136 Rear number plate lamp
137 Heated rear screen
138 Right rear light cluster
139 Rear foglamp go-ahead switch
140 Join between front cable and antiskid
brakes cables
141 Join between front cable and antiskid
brakes cables
142 25 A fuse for antiskid brakes
143 Antiskid braking system control unit
144 Left modulator for antiskid brakes
145 Right modulator for antiskid brakes
146 Sensor on left front wheel
147 Sensor on right front wheel
148 10A fuse for antiskid braking system
149 Vacuum switch for antiskid braking
system
150 Antiskid braking system engagement
relay
151 Antiskid braking system failure
signalling switch
152 Digiplex electronic ignition control
unitNo Description
153 Bosch SPi Mono-Jetronic injection
system control unit
155 Join between engine cable and
injection cables
156 Join between engine cable and rear
cables for SPi system
157 Idle adjustment actuator
158 Throttle position switch
159 Injector current restriction resistor
(SPi)
162 Engine cut-out solenoid
163 Idle cut-out solenoid valve
168 Tachometer electro-magnetic sensor
169 Automatic heater control unit
170 Heater fan
171 Outside temperature sensor
172 Mixed air temperature sensor
173 Air mixture flap electrical control
motor
174 Diagnostic socket for automatic
heater
175 Connector block
176 Connector block
177 Join with cables for automatic heater
178 Radiator coolant circulation solenoid
valve
179 Automatic heater unit:
A Temperature control potentiometer
B Fan speed control potentiometer
C Heater controls light bulbs
D Ideogram signalling automatic
function engaged
E Automatic function engaged
switch
180 Horn
181 Check Panel:
A Insufficient engine oil level warning
light
B Insufficient coolant level warning
light
C Failure with side lights/rear
foglamp/rear number
plate light/braking lights warning light
D Insufficient brake fluid level
warning light
E Door ajar warning light
F Brake pad wear warning light
182 Earth on dashboard
183 Join with cables for central locking
184 Join with cables for central locking
185 Left rear central locking geared motor
186 Right rear central locking geared
motor
187 Contact on choke lever
188 Resistor for inlet manifold heating
189 Pre-heating thermal switch
191 Heated Lambda sensor
192 Lambda sensor protective fuse
193 Silicon diode
194 Join between front cable and injection
cable
197 Connector blockNo Description
198 Rear cable join
199 Insufficient engine oil level sensor
200 Insufficient coolant level sensor
201 Switch signalling left rear door ajar
202 Switch signalling right rear door ajar
203 Switch on gear selector
204 Light for gear selector panel signalling
gear engaged
205 Parking signal not on
206 Connector block
207 Join in engine compartment with
injection cables
208 Petrol vapour cut out-solenoid valve
209 Petrol vapour cut out-solenoid valve
210 Airflow meter
211 Speedometer relay
212 LE2 Jetronic electronic injection
control unit
213 Connector block
214 Connector block
215 Connector block
216 Ignition cable join
217 Join between front cable and
emission control cable
218 Join between front cable and battery
cable
219 Injection system air temperature
sensor
220 Ignition control unit relay feed
225 Front cable join
226 Front cable join
227 Dim-dip circuit cut out switch
228 Dim-dip circuit resistance
229 Dim-dip circuit 7.5 A protective fuse
230 Driver’s side seat heated pad
231 Driver’s seat backrest heated pad
232 10 A protective fuse for driver’s seat
heated pads
233 Foglamps go-ahead switch
234 Driving lights cut out switch
235 Dipped headlamps relay
236 Main beam headlamps relay
237 Join between engine cable and
dashboard cables
Wire colour codes
A Light blue
B White
C Orange
G Yellow
H Grey
L Blue
M Brown
N Black
R Red
S Pink
V Green
Z Violet
Example of two-colour wire:
BN (White/Black)

REF•8General Repair Procedures
Whenever servicing, repair or overhaul work
is carried out on the car or its components,
observe the following procedures and
instructions. This will assist in carrying out the
operation efficiently and to a professional
standard of workmanship.
Joint mating faces and gaskets
When separating components at their
mating faces, never insert screwdrivers or
similar implements into the joint between the
faces in order to prise them apart. This can
cause severe damage which results in oil
leaks, coolant leaks, etc upon reassembly.
Separation is usually achieved by tapping
along the joint with a soft-faced hammer in
order to break the seal. However, note that
this method may not be suitable where
dowels are used for component location.
Where a gasket is used between the mating
faces of two components, a new one must be
fitted on reassembly; fit it dry unless otherwise
stated in the repair procedure. Make sure that
the mating faces are clean and dry, with all
traces of old gasket removed. When cleaning a
joint face, use a tool which is unlikely to score
or damage the face, and remove any burrs or
nicks with an oilstone or fine file.
Make sure that tapped holes are cleaned
with a pipe cleaner, and keep them free of
jointing compound, if this is being used,
unless specifically instructed otherwise.
Ensure that all orifices, channels or pipes
are clear, and blow through them, preferably
using compressed air.
Oil seals
Oil seals can be removed by levering them
out with a wide flat-bladed screwdriver or
similar implement. Alternatively, a number of
self-tapping screws may be screwed into the
seal, and these used as a purchase for pliers or
some similar device in order to pull the seal free.
Whenever an oil seal is removed from its
working location, either individually or as part
of an assembly, it should be renewed.
The very fine sealing lip of the seal is easily
damaged, and will not seal if the surface it
contacts is not completely clean and free from
scratches, nicks or grooves. If the original
sealing surface of the component cannot be
restored, and the manufacturer has not made
provision for slight relocation of the seal
relative to the sealing surface, the component
should be renewed.
Protect the lips of the seal from any surface
which may damage them in the course of
fitting. Use tape or a conical sleeve where
possible. Lubricate the seal lips with oil before
fitting and, on dual-lipped seals, fill the space
between the lips with grease.
Unless otherwise stated, oil seals must be
fitted with their sealing lips toward the
lubricant to be sealed.
Use a tubular drift or block of wood of the
appropriate size to install the seal and, if the
seal housing is shouldered, drive the seal
down to the shoulder. If the seal housing isunshouldered, the seal should be fitted with
its face flush with the housing top face (unless
otherwise instructed).
Screw threads and fastenings
Seized nuts, bolts and screws are quite a
common occurrence where corrosion has set
in, and the use of penetrating oil or releasing
fluid will often overcome this problem if the
offending item is soaked for a while before
attempting to release it. The use of an impact
driver may also provide a means of releasing
such stubborn fastening devices, when used
in conjunction with the appropriate
screwdriver bit or socket. If none of these
methods works, it may be necessary to resort
to the careful application of heat, or the use of
a hacksaw or nut splitter device.
Studs are usually removed by locking two
nuts together on the threaded part, and then
using a spanner on the lower nut to unscrew
the stud. Studs or bolts which have broken off
below the surface of the component in which
they are mounted can sometimes be removed
using a stud extractor. Always ensure that a
blind tapped hole is completely free from oil,
grease, water or other fluid before installing
the bolt or stud. Failure to do this could cause
the housing to crack due to the hydraulic
action of the bolt or stud as it is screwed in.
When tightening a castellated nut to accept
a split pin, tighten the nut to the specified
torque, where applicable, and then tighten
further to the next split pin hole. Never slacken
the nut to align the split pin hole, unless stated
in the repair procedure.
When checking or retightening a nut or bolt
to a specified torque setting, slacken the nut
or bolt by a quarter of a turn, and then
retighten to the specified setting. However,
this should not be attempted where angular
tightening has been used.
For some screw fastenings, notably
cylinder head bolts or nuts, torque wrench
settings are no longer specified for the latter
stages of tightening, “angle-tightening” being
called up instead. Typically, a fairly low torque
wrench setting will be applied to the
bolts/nuts in the correct sequence, followed
by one or more stages of tightening through
specified angles.
Locknuts, locktabs and washers
Any fastening which will rotate against a
component or housing during tightening
should always have a washer between it and
the relevant component or housing.
Spring or split washers should always be
renewed when they are used to lock a critical
component such as a big-end bearing
retaining bolt or nut. Locktabs which are
folded over to retain a nut or bolt should
always be renewed.
Self-locking nuts can be re-used in non-
critical areas, providing resistance can be felt
when the locking portion passes over the bolt
or stud thread. However, it should be noted
that self-locking stiffnuts tend to lose theireffectiveness after long periods of use, and
should then be renewed as a matter of course.
Split pins must always be replaced with
new ones of the correct size for the hole.
When thread-locking compound is found
on the threads of a fastener which is to be re-
used, it should be cleaned off with a wire
brush and solvent, and fresh compound
applied on reassembly.
Special tools
Some repair procedures in this manual
entail the use of special tools such as a press,
two or three-legged pullers, spring com-
pressors, etc. Wherever possible, suitable
readily-available alternatives to the manu-
facturer’s special tools are described, and are
shown in use. In some instances, where no
alternative is possible, it has been necessary
to resort to the use of a manufacturer’s tool,
and this has been done for reasons of safety
as well as the efficient completion of the repair
operation. Unless you are highly-skilled and
have a thorough understanding of the
procedures described, never attempt to
bypass the use of any special tool when the
procedure described specifies its use. Not
only is there a very great risk of personal
injury, but expensive damage could be
caused to the components involved.
Environmental considerations
When disposing of used engine oil, brake
fluid, antifreeze, etc, give due consideration to
any detrimental environmental effects. Do not,
for instance, pour any of the above liquids
down drains into the general sewage system,
or onto the ground to soak away. Many local
council refuse tips provide a facility for waste
oil disposal, as do some garages. If none of
these facilities are available, consult your local
Environmental Health Department, or the
National Rivers Authority, for further advice.
With the universal tightening-up of legis-
lation regarding the emission of environmen-
tally-harmful substances from motor vehicles,
most vehicles have tamperproof devices fitted
to the main adjustment points of the fuel
system. These devices are primarily designed
to prevent unqualified persons from adjusting
the fuel/air mixture, with the chance of a
consequent increase in toxic emissions. If
such devices are found during servicing or
overhaul, they should, wherever possible, be
renewed or refitted in accordance with the
manufacturer’s requirements or current
legislation.
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.

Engine cuts out suddenly –
ignition fault
m mLoose or disconnected LT wires
m mWet HT leads or distributor cap (after
traversing water splash)
m mCoil failure (check for spark)
m mOther ignition fault (see Chapter 4)
Engine misfires before cutting out
– fuel fault
m mFuel tank empty
m mFuel pump defective or filter blocked
(check for delivery)
m mFuel tank filler vent blocked (suction will be
evident on releasing cap)
m mCarburettor needle valve sticking
m mCarburettor jets blocked (fuel contami-
nated)
m mOther fuel system fault (see Chapter 3)
Engine cuts out – other causes
m
mSerious overheating
m mMajor mechanical failure (eg camshaft
drive)
Ignition (no-charge) warning light
illuminated
m mSlack or broken drivebelt — retension or
renew (Chapter 9)
Ignition warning light not
illuminated
m mCoolant loss due to internal or external
leakage (see Chapter 2)
m mThermostat defective
m mLow oil level
m mBrakes binding
m mRadiator clogged externally or internally
m mElectric cooling fan not operating correctly
m mEngine waterways clogged
m mIgnition timing incorrect or automatic
advance malfunctioning
m mMixture too weak
Note: Do not add cold water to an overheated
engine or damage may result
Note: Low oil pressure in a high-mileage
engine at tickover is not necessarily a cause
for concern. Sudden pressure loss at speed is
far more significant. In any event check the
gauge or warning light sender before
condemning the engine.
Gauge reads low or warning light
illuminated with engine running
m mOil level low or incorrect grade
m mDefective gauge or sender unit m mWire to sender unit earthed
m mEngine overheating
m mOil filter clogged or bypass valve defective
m mOil pressure relief valve defective
m mOil pick-up strainer clogged
m mOil pump worn or mountings loose
m mWorn main or big-end bearings
Pre-ignition (pinking) on
acceleration
m mIncorrect grade of fuel
m mIgnition timing incorrect
m mDistributor faulty or worn
m mWorn or maladjusted carburettor
m mExcessive carbon build-up in engine
Whistling or wheezing noises
m
mLeaking vacuum hose
m mLeaking carburettor or manifold gasket
m mBlowing head gasket
Tapping or rattling
m
mIncorrect valve clearances (where appli-
cable)
m mWorn valve gear
m mWorn timing chain or belt
m mBroken piston ring (ticking noise)
Knocking or thumping
m
mUnintentional mechanical contact (eg fan
blades)
m mWorn drivebelt
m mPeripheral component fault (generator,
water pump, etc)
m mWorn big-end bearings (regular heavy
knocking, perhaps less under load)
m mWorn main bearings (rumbling and
knocking, perhaps worsening under load)
m mPiston slap (most noticeable when cold)
Engine noises
Low engine oil pressure
Engine overheatsEngine cuts out and will not restart
Fault FindingREF•11
REF
Crank engine and check for spark. Note
use of insulated tool

Glossary of Technical TermsREF•13
REF
A
ABS (Anti-lock brake system)A system,
usually electronically controlled, that senses
incipient wheel lockup during braking and
relieves hydraulic pressure at wheels that are
about to skid.
Air bag An inflatable bag hidden in the
steering wheel (driver’s side) or the dash or
glovebox (passenger side). In a head-on
collision, the bags inflate, preventing the
driver and front passenger from being thrown
forward into the steering wheel or windscreen.
Air cleanerA metal or plastic housing,
containing a filter element, which removes
dust and dirt from the air being drawn into the
engine.
Air filter elementThe actual filter in an air
cleaner system, usually manufactured from
pleated paper and requiring renewal at regular
intervals.
Allen keyA hexagonal wrench which fits into
a recessed hexagonal hole.
Alligator clipA long-nosed spring-loaded
metal clip with meshing teeth. Used to make
temporary electrical connections.
AlternatorA component in the electrical
system which converts mechanical energy
from a drivebelt into electrical energy to
charge the battery and to operate the starting
system, ignition system and electrical
accessories.
Ampere (amp)A unit of measurement for the
flow of electric current. One amp is the
amount of current produced by one volt
acting through a resistance of one ohm.
Anaerobic sealerA substance used to
prevent bolts and screws from loosening.
Anaerobic means that it does not require
oxygen for activation. The Loctite brand is
widely used.
AntifreezeA substance (usually ethylene
glycol) mixed with water, and added to a
vehicle’s cooling system, to prevent freezing
of the coolant in winter. Antifreeze also
contains chemicals to inhibit corrosion and
the formation of rust and other deposits that
would tend to clog the radiator and coolant
passages and reduce cooling efficiency.
Anti-seize compoundA coating that
reduces the risk of seizing on fasteners that
are subjected to high temperatures, such as
exhaust manifold bolts and nuts.
AsbestosA natural fibrous mineral with great
heat resistance, commonly used in the
composition of brake friction materials.Asbestos is a health hazard and the dust
created by brake systems should never be
inhaled or ingested.
AxleA shaft on which a wheel revolves, or
which revolves with a wheel. Also, a solid
beam that connects the two wheels at one
end of the vehicle. An axle which also
transmits power to the wheels is known as a
live axle.
AxleshaftA single rotating shaft, on either
side of the differential, which delivers power
from the final drive assembly to the drive
wheels. Also called a driveshaft or a halfshaft.
BBall bearingAn anti-friction bearing
consisting of a hardened inner and outer race
with hardened steel balls between two races.
BearingThe curved surface on a shaft or in a
bore, or the part assembled into either, that
permits relative motion between them with
minimum wear and friction.
Big-end bearingThe bearing in the end of
the connecting rod that’s attached to the
crankshaft.
Bleed nippleA valve on a brake wheel
cylinder, caliper or other hydraulic component
that is opened to purge the hydraulic system
of air. Also called a bleed screw.
Brake bleedingProcedure for removing air
from lines of a hydraulic brake system.
Brake discThe component of a disc brake
that rotates with the wheels.Brake drumThe component of a drum brake
that rotates with the wheels.
Brake liningsThe friction material which
contacts the brake disc or drum to retard the
vehicle’s speed. The linings are bonded or
riveted to the brake pads or shoes.
Brake padsThe replaceable friction pads
that pinch the brake disc when the brakes are
applied. Brake pads consist of a friction
material bonded or riveted to a rigid backing
plate.
Brake shoeThe crescent-shaped carrier to
which the brake linings are mounted and
which forces the lining against the rotating
drum during braking.
Braking systemsFor more information on
braking systems, consult the Haynes
Automotive Brake Manual.
Breaker barA long socket wrench handle
providing greater leverage.
BulkheadThe insulated partition between
the engine and the passenger compartment.
CCaliperThe non-rotating part of a disc-brake
assembly that straddles the disc and carries
the brake pads. The caliper also contains the
hydraulic components that cause the pads to
pinch the disc when the brakes are applied. A
caliper is also a measuring tool that can be set
to measure inside or outside dimensions of an
object.
CamshaftA rotating shaft on which a series
of cam lobes operate the valve mechanisms.
The camshaft may be driven by gears, by
sprockets and chain or by sprockets and a
belt.
CanisterA container in an evaporative
emission control system; contains activated
charcoal granules to trap vapours from the
fuel system.
CarburettorA device which mixes fuel with
air in the proper proportions to provide a
desired power output from a spark ignition
internal combustion engine.
CastellatedResembling the parapets along
the top of a castle wall. For example, a
castellated balljoint stud nut.
CastorIn wheel alignment, the backward or
forward tilt of the steering axis. Castor is
positive when the steering axis is inclined
rearward at the top.
Canister
Brake bleeding
Bearing
Air filter

Glossary of Technical TermsREF•15
REF
GGapThe distance the spark must travel in
jumping from the centre electrode to the side
electrode in a spark plug. Also refers to the
spacing between the points in a contact
breaker assembly in a conventional points-
type ignition, or to the distance between the
reluctor or rotor and the pickup coil in an
electronic ignition.
GasketAny thin, soft material - usually cork,
cardboard, asbestos or soft metal - installed
between two metal surfaces to ensure a good
seal. For instance, the cylinder head gasket
seals the joint between the block and the
cylinder head.
GaugeAn instrument panel display used to
monitor engine conditions. A gauge with a
movable pointer on a dial or a fixed scale is an
analogue gauge. A gauge with a numerical
readout is called a digital gauge.
HHalfshaftA rotating shaft that transmits
power from the final drive unit to a drive
wheel, usually when referring to a live rear
axle.
Harmonic balancerA device designed to
reduce torsion or twisting vibration in the
crankshaft. May be incorporated in the
crankshaft pulley. Also known as a vibration
damper.
HoneAn abrasive tool for correcting small
irregularities or differences in diameter in an
engine cylinder, brake cylinder, etc.
Hydraulic tappetA tappet that utilises
hydraulic pressure from the engine’s
lubrication system to maintain zero clearance
(constant contact with both camshaft and
valve stem). Automatically adjusts to variation
in valve stem length. Hydraulic tappets also
reduce valve noise.
IIgnition timingThe moment at which the
spark plug fires, usually expressed in the
number of crankshaft degrees before the
piston reaches the top of its stroke.
Inlet manifoldA tube or housing with
passages through which flows the air-fuel
mixture (carburettor vehicles and vehicles with
throttle body injection) or air only (port fuel-
injected vehicles) to the port openings in the
cylinder head.
JJump startStarting the engine of a vehicle
with a discharged or weak battery by
attaching jump leads from the weak battery to
a charged or helper battery.
LLoad Sensing Proportioning Valve (LSPV)A
brake hydraulic system control valve that
works like a proportioning valve, but also
takes into consideration the amount of weight
carried by the rear axle.
LocknutA nut used to lock an adjustment
nut, or other threaded component, in place.
For example, a locknut is employed to keep
the adjusting nut on the rocker arm in
position.
LockwasherA form of washer designed to
prevent an attaching nut from working loose.
MMacPherson strutA type of front
suspension system devised by Earle
MacPherson at Ford of England. In its original
form, a simple lateral link with the anti-roll bar
creates the lower control arm. A long strut - an
integral coil spring and shock absorber - is
mounted between the body and the steering
knuckle. Many modern so-called MacPherson
strut systems use a conventional lower A-arm
and don’t rely on the anti-roll bar for location.
MultimeterAn electrical test instrument with
the capability to measure voltage, current and
resistance.
NNOxOxides of Nitrogen. A common toxic
pollutant emitted by petrol and diesel engines
at higher temperatures.
OOhmThe unit of electrical resistance. One
volt applied to a resistance of one ohm will
produce a current of one amp.
OhmmeterAn instrument for measuring
electrical resistance.
O-ringA type of sealing ring made of a
special rubber-like material; in use, the O-ring
is compressed into a groove to provide the
sealing action.
Overhead cam (ohc) engineAn engine with
the camshaft(s) located on top of the cylinder
head(s).Overhead valve (ohv) engineAn engine with
the valves located in the cylinder head, but
with the camshaft located in the engine block.
Oxygen sensorA device installed in the
engine exhaust manifold, which senses the
oxygen content in the exhaust and converts
this information into an electric current. Also
called a Lambda sensor.
PPhillips screwA type of screw head having a
cross instead of a slot for a corresponding
type of screwdriver.
PlastigageA thin strip of plastic thread,
available in different sizes, used for measuring
clearances. For example, a strip of Plastigage
is laid across a bearing journal. The parts are
assembled and dismantled; the width of the
crushed strip indicates the clearance between
journal and bearing.
Propeller shaftThe long hollow tube with
universal joints at both ends that carries
power from the transmission to the differential
on front-engined rear wheel drive vehicles.
Proportioning valveA hydraulic control
valve which limits the amount of pressure to
the rear brakes during panic stops to prevent
wheel lock-up.
RRack-and-pinion steeringA steering system
with a pinion gear on the end of the steering
shaft that mates with a rack (think of a geared
wheel opened up and laid flat). When the
steering wheel is turned, the pinion turns,
moving the rack to the left or right. This
movement is transmitted through the track
rods to the steering arms at the wheels.
RadiatorA liquid-to-air heat transfer device
designed to reduce the temperature of the
coolant in an internal combustion engine
cooling system.
RefrigerantAny substance used as a heat
transfer agent in an air-conditioning system.
R-12 has been the principle refrigerant for
many years; recently, however, manufacturers
have begun using R-134a, a non-CFC
substance that is considered less harmful to
the ozone in the upper atmosphere.
Rocker armA lever arm that rocks on a shaft
or pivots on a stud. In an overhead valve
engine, the rocker arm converts the upward
movement of the pushrod into a downward
movement to open a valve.
Adjusting spark plug gap
Plastigage
Gasket

REF•16Glossary of Technical Terms
RotorIn a distributor, the rotating device
inside the cap that connects the centre
electrode and the outer terminals as it turns,
distributing the high voltage from the coil
secondary winding to the proper spark plug.
Also, that part of an alternator which rotates
inside the stator. Also, the rotating assembly
of a turbocharger, including the compressor
wheel, shaft and turbine wheel.
RunoutThe amount of wobble (in-and-out
movement) of a gear or wheel as it’s rotated.
The amount a shaft rotates “out-of-true.” The
out-of-round condition of a rotating part.
SSealantA liquid or paste used to prevent
leakage at a joint. Sometimes used in
conjunction with a gasket.
Sealed beam lampAn older headlight design
which integrates the reflector, lens and
filaments into a hermetically-sealed one-piece
unit. When a filament burns out or the lens
cracks, the entire unit is simply replaced.
Serpentine drivebeltA single, long, wide
accessory drivebelt that’s used on some
newer vehicles to drive all the accessories,
instead of a series of smaller, shorter belts.
Serpentine drivebelts are usually tensioned by
an automatic tensioner.
ShimThin spacer, commonly used to adjust
the clearance or relative positions between
two parts. For example, shims inserted into or
under bucket tappets control valve
clearances. Clearance is adjusted by
changing the thickness of the shim.
Slide hammerA special puller that screws
into or hooks onto a component such as a
shaft or bearing; a heavy sliding handle on the
shaft bottoms against the end of the shaft to
knock the component free.SprocketA tooth or projection on the
periphery of a wheel, shaped to engage with a
chain or drivebelt. Commonly used to refer to
the sprocket wheel itself.
Starter inhibitor switchOn vehicles with an
automatic transmission, a switch that
prevents starting if the vehicle is not in Neutral
or Park.
StrutSee MacPherson strut.
TTappetA cylindrical component which
transmits motion from the cam to the valve
stem, either directly or via a pushrod and
rocker arm. Also called a cam follower.
ThermostatA heat-controlled valve that
regulates the flow of coolant between the
cylinder block and the radiator, so maintaining
optimum engine operating temperature. A
thermostat is also used in some air cleaners in
which the temperature is regulated.
Thrust bearingThe bearing in the clutch
assembly that is moved in to the release
levers by clutch pedal action to disengage the
clutch. Also referred to as a release bearing.
Timing beltA toothed belt which drives the
camshaft. Serious engine damage may result
if it breaks in service.
Timing chainA chain which drives the
camshaft.
Toe-inThe amount the front wheels are
closer together at the front than at the rear. On
rear wheel drive vehicles, a slight amount of
toe-in is usually specified to keep the front
wheels running parallel on the road by
offsetting other forces that tend to spread the
wheels apart.
Toe-outThe amount the front wheels are
closer together at the rear than at the front. On
front wheel drive vehicles, a slight amount of
toe-out is usually specified.
ToolsFor full information on choosing and
using tools, refer to the Haynes Automotive
Tools Manual.
TracerA stripe of a second colour applied to
a wire insulator to distinguish that wire from
another one with the same colour insulator.
Tune-upA process of accurate and careful
adjustments and parts replacement to obtain
the best possible engine performance.TurbochargerA centrifugal device, driven by
exhaust gases, that pressurises the intake air.
Normally used to increase the power output
from a given engine displacement, but can
also be used primarily to reduce exhaust
emissions (as on VW’s “Umwelt” Diesel
engine).
UUniversal joint or U-jointA double-pivoted
connection for transmitting power from a
driving to a driven shaft through an angle. A
U-joint consists of two Y-shaped yokes and a
cross-shaped member called the spider.
VValveA device through which the flow of
liquid, gas, vacuum, or loose material in bulk
may be started, stopped, or regulated by a
movable part that opens, shuts, or partially
obstructs one or more ports or passageways.
A valve is also the movable part of such a
device.
Valve clearanceThe clearance between the
valve tip (the end of the valve stem) and the
rocker arm or tappet. The valve clearance is
measured when the valve is closed.
Vernier caliperA precision measuring
instrument that measures inside and outside
dimensions. Not quite as accurate as a
micrometer, but more convenient.
ViscosityThe thickness of a liquid or its
resistance to flow.
VoltA unit for expressing electrical
“pressure” in a circuit. One volt that will
produce a current of one ampere through a
resistance of one ohm.
WWeldingVarious processes used to join metal
items by heating the areas to be joined to a
molten state and fusing them together. For
more information refer to the Haynes
Automotive Welding Manual.
Wiring diagramA drawing portraying the
components and wires in a vehicle’s electrical
system, using standardised symbols. For
more information refer to the Haynes
Automotive Electrical and Electronic Systems
Manual.
Serpentine drivebelt

A
Accelerator cable - 3•12, 13•80
Accelerator control system - 13•75
Accelerator pump -3•7, 3•8, 3•11, 13•66
Acknowledgements - 0•4
Aerial -9•10
Air bags - 0•5
Air cleaner -3•4, 13•60, 13•69, 13•67,
13•75, 13•79
Air pressure switch - 13•70
Air temperature sensor - 13•76
Airflow meter - 13•67, 13•69, 13•80
Alternator -9•3, 13•58, 13•103, 13•104
Alternator fault -9•14
Anti-flooding device -3•8, 3•9, 3•10, 3•11,
13•64
Anti-knock sensor - 13•86, 13•90
Anti-roll bar - 13•111
Antifreeze - 0•6, 0•13, 2•1, 2•2
Antiskid system - 13•103
Armrest - 13•112
Asbestos - 0•5
Auxiliary shaft -1•29, 1•30, 13•51, 13•53
B
Battery -0•5, 9•2
Battery fault -9•14
Bleeding brakes -8•7
Bleeding clutch - 13•94
Bodywork- 12•1et seq, 13•111, REF•4
Bonnet - 12•3, 12•4
Boots -7•2, 10•2, 13•98
Brake fluid -0•13, 8•1, 13•110, 13•111
Braking system-8•1et seq, 13•100,
REF•1, REF•2, REF•3
Braking system fault finding -8•9
Breakerless ignition system - 13•85, 13•86
Bumpers - 12•4, 12•11, 13•113
Burning -0•5
C
Cables -3•12, 5•1, 8•9, 9•8, 13•80
Calipers -8•3, 13•101, 13•102Camshaft -1•19, 1•21, 1•24, 1•29, 1•32,
13•21, 13•30, 13•34, 13•41, 13•42
Capacities -0•6, 13•17
Carburettors -3•6 to 3•11, 13•62 to 13•66
Carpets - 12•2
Cassette player-9•10
Catalytic converter - 13•77
Central door locking -9•11, 13•109
Centre console - 12•9
Check control (warning module) system -
9•12, 9•13, 13•110, 13•111
Choke -3•11, 3•12
Cigar lighter -9•13, 13•109
Clock -9•13, 13•108
Clutch-5•1et seq, 13•83, 13•92, 13•94
Clutch fault finding -5•3
Clutch fluid -0•13
CO emissions (mixture) - REF•4
Coil -4•6, 13•86, 13•90, 13•91
Coil spring - 11•3, 11•4
Condenser -4•5
Connecting rods -1•12, 1•18, 1•22, 1•26,
1•30, 13•25, 13•26, 13•30, 13•35,
13•47, 13•48, 13•53
Console - 12•9
Constant velocity joint -0•13, 7•3, 13•98,
13•99
Contact breaker points -4•2, 4•3
Contents -0•2
Control panel - 13•108
Conversion factors -0•14
Coolant -0•6, 0•13, 2•1, 2•2, 13•69, 13•70,
13•110, 13•111
Coolant pump -2•4, 13•55, 13•58
Cooling and heating systems-2•1et seq,
13•54, 13•55
Cooling and heating systems fault finding -
2•8
Courtesy lamp -9•5, 9•8
Crankcase -1•17
Crankcase ventilation system -1•8
Crankshaft -1•18, 1•20, 1•30, 1•31, 13•44,
13•45, 13•52
Crossmember - 11•4
Crushing -0•5
CV joints -0•13, 7•3, 13•98, 13•99
Cylinder block -1•17Cylinder head -1•10, 1•16, 1•19, 1•22,
1•25, 1•28, 1•32, 13•19, 13•22, 13•30,
13•34, 13•43, 13•44, 13•53
D
Dents in bodywork - 12•2
Depressurisation (fuel system) - 13•75
Digiplex 2 ignition system - 13•90
Dim-dip system - 13•106
Dimensions -0•6, 13•17
Direction indicators -9•7
Discs -8•4, 13•101, 13•102
Distributor -4•3, 4•5, 13•86, 13•89, 13•90,
13•92
Doors -9•11, 12•5, 12•6, 12•7, 13•111,
13•112, 13•114, REF•2
Drivebelts -2•3, 13•58
Driveshaft
Driveshafts and hubs fault finding -7•6
Driveshafts,hubs,roadwheels and tyres-
0•13, 7•1et seq, 10•4, 11•3, 11•6,
13•98, 13•99, REF•3, REF•4
Drums -8•4
Dwell angle -4•4
E
Economy gauge (Econometer) -3•11, 9•12
Electric shock -0•5
Electric windows -9•11, 13•109
Electrical control circuit (ECU) - 13•67,
13•71, 13•81, 13•86, 13•90
Electrical system-9•1et seq,13•103,
REF•2
Electrical system fault finding -9•14,
REF•9
Electronic ignition -4•3, 4•6, 4•7
Engine-1•1et seq, 13•19, 13•33, 13•37
Engine fault finding -1•35, 1•36, 2•8, 3•13,
4•9, 13•92, REF•10, REF•11
Engine oil -0•6, 0•13, 1•3, 1•4, 1•8
Engine speed sensor -4•7, 13•89, 13•91
Environmental considerations - REF•8
Exhaust emission checks - REF•4
Exhaust manifold - 13•77
Exhaust system -3•12, REF•3
IndexREF•17
REF
Note: References throughout this index relate to Chapter•page number