1983 FIAT UNO coolant level

0•10Routine maintenance
Maintenance is essential for ensuring safety and desirable for the
purpose of getting the best in terms of performance and economy
from the car. Over the years the need for periodic lubrication has been
greatly reduced if not totally eliminated. This has unfortunately tended
to lead some owners to think that because no such action is required
the items either no longer exist or will last forever. This is certainly not
the case; it is essential to carry out regular visual examinations as
comprehensively as possible in order to spot any possible defects at
an early stage before they develop into major and expensive repairs.
For information applicable to later models, see Supplement.
Every 250 miles (400 km), weekly,
or before a long journey
m mCheck engine oil level
m mCheck brake reservoir fluid level
m mCheck tyre pressures
m mCheck operation of all lights and horn
m mTop up washer fluid reservoirs, adding a screen
wash, and check operation of washers and wipers
m mCheck coolant level
m mCheck battery electrolyte level
Every 6000 miles (10 000 km)
or six months, whichever comes first
m mRenew engine oil and filter (Chapter 1, Section 2)
m mCheck drivebelt tension (Chapter 2, Section 8)
m mCheck carburettor idle speed and mixture
adjustments (Chapter 3)
m mCheck contact points and dwell angle (mechanical
breaker distributors) (Chapter 4, Section 3)
m mCheck tyre tread wear (Chapter 7, Section 7)
m mCheck disc pads for wear (Chapter 8, Section 3)
Every 36 000 miles (60 000 km)
or three years, whichever comes first
m mRenew the timing belt - 1116 and 1299/1301 cc
(Chapter 1, Section 28)
m mCheck exhaust system for corrosion (Chapter 3,
Section 19)
m mRenew contact breaker points and adjust dwell
angle (mechanical breaker distributors) (Chapter 4,
Section 3)
m mCheck and adjust ignition timing (Chapter 4,
Section 4)
m mRenew spark plugs (Chapter 4, Section 11)
m mCheck clutch adjustment (Chapter 5, Section 2)
m mCheck transmission oil level (Chapter 6, Section 2)
m mCheck driveshaft and steering rack gaiters for splits
(Chapters 7 and 10)
m mCheck rear brake shoe linings for wear (Chapter 8,
Section 4)
m mCheck handbrake travel (Chapter 8, Section 16)
m mCheck headlamp beam alignment (Chapter 9,
Section 17)
m mCheck balljoints for wear (Chapter 10, Section 2)
m mCheck front wheel alignment (Chapter 10, Section 8)
m mCheck suspension bushes for wear (Chapter 11,
Section 2)
m mCheck seat belts for fraying (Chapter 12, Section 23)
m mLubricate controls, hinges and locks
Every 24 000 miles (40 000 km)
or two years, whichever comes first
m mRenew coolant anti-freeze mixture (Chapter 2,
Section 3)
m mRenew transmission oil (Chapter 6, Section 2)
m mRenew brake hydraulic fluid (Chapter 8, Section 12)
m mCheck for underbody corrosion and clean out door
and sill drain holes (Chapter 12, Section 2)
Every 12 000 miles (20 000 km) or
12 months, whichever comes first
m mCheck and adjust valve clearances (Chapter 1,
Sections 5 and 26)
m mRenew air cleaner element (Chapter 3, Section 2)

to the engine. Also reconnect the brake servo
hose to the intake manifold (photos).
22Reconnect the leads to the reversing lamp
switch. Reconnect the transmission earth lead
(photos).
23Reconnect the clutch cable and adjust as
described in Chapter 5.
24Reconnect the speedometer drive cable
to the transmission and tighten the knurled
retaining ring.
25Reconnect the low tension lead to the
distributor and the high tension lead to the
ignition coil.
26Reconnnect the electrical leads to thestarter motor, the oil pressure and
temperature switches and the coolant
temperature switch.
27Connect the leads to the alternator.
28Refit the air cleaner.
29Refill the cooling system. Refill the engine
with oil.
30Reconnect the battery.
31Refit the bonnet and connect the
windscreen washer tube.
32Fit the inner wing protective shields
(photo).
45 Engine- initial start-up after
major overhaul
4
1If new bearings and rings have been fitted,
it is likely that the engine will be stiff to turn so
make sure the battery is well charged.
2Switch on the ignition and check that
appropriate warning lights come on.
3Start up the engine. If it refuses to start,
refer to the “Fault Finding” Section in the
Reference section of this Manual.
4Watch the oil pressure warning light and
alternator charging indicator light. If there is
no charge or if the oil pressure warning light
does not go out after a second or two, havinghad time to fill the new oil filter, switch off and
recheck.
5If the warning lights go out, set the engine
to run on fast idle and check the engine for
leaks.
6Check the coolant level; it will probably go
down as air locks are filled.
7Keep the engine running at a fast idle and
bring it up to normal working temperature. As
the engine warms up, there will be some odd
smells and smoke from parts getting hot and
burning off oil deposits.
8When the engine running temperature has
been reached, adjust the idling speed, as
described in Chapter 3. Check and, if
necessary, adjust the ignition timing using a
stroboscope (see Chapter 4).
9Stop the engine and wait a few minutes;
check to see if there are any coolant or oil
leaks.
10Road test the car to check that the engine
is running with the correct smoothness and
power. If it does not, refer to “Fault finding” in
the Reference section of this Manual. Do not
race the engine. If new bearings and/or
pistons and rings have been fitted, it should
be treated as a new engine and run it at
reduced speed for at east 800 km (500 miles).
11After 800 km (500 miles) change the
engine oil and filter.
1•34 1116 cc and 1301 cc engine
44.32 Inner wing protective shield44.26B Coolant temperature switch44.26A Oil pressure warning switch
44.22B Transmission earth lead
44.22A Reversing lamp switch on
transmission44.21B Brake servo hose at manifold44.21A Heater hose at manifold

Engine idles roughly
m mMixture too weak
m mAir leak in carburettor
m mAir leak at inlet manifold to cylinder head, or inlet manifold to
carburettor
m mCarburettor incorrectly adjusted
m mOther fuel system fault (see Chapter 3)
m mLow tension leads on coil loose
m mLow tension lead to distributor loose
m mDirty, incorrectly set, or pitted contact breaker points
m mTracking across inside of distributor cover
m mFaulty coil
m mIgnition leads loose
m mSpark plugs fouled or incorrectly gapped.
m mIgnition timing incorrect
m mOther ignition fault (see Chapter 4)
m mIncorrect valve clearances
m mWidely differing cylinder compressions
m mLow battery voltage (charging fault)
m mBattery leads loose on terminals
m mBattery earth strap loose on body attachment point
m mEngine earth lead loose
Pre-ignition (pinking) during acceleration
m
mIncorrect grade of fuel being used
m mIgnition timing over-advanced
m mOther ignition fault (see Chapter 4)
m mEngine overheated
m mExcessive carbon build-up
m mFuel system fault (see Chapter 3)
m mValve timing incorrect (after rebuild)
m mMixture too weak
Engine runs on after switching off
m
mIdle speed too high
m mIncorrect type of spark plug
m mOverheating
m mExcessive carbon build-up
m mOther emission control fault (see Chapter 3)
Oil being lost due to leaks
m
mLeaking oil filter gasket
m mLeaking rocker cover gasket
m mLeaking timing gear cover gasket
m mLeaking sump gasket
m mLoose sump plug
Low oil pressure (verify accuracy of sender before
dismantling engine!)
m mOil level low
m mEngine overheating
m mIncorrect grade of oil in use
m mOil filter clogged or bypass valve stuck
m mPressure relief valve stuck or defective
m mOil pick-up strainer clogged or loose
m mMain or big-end bearings worn
m mOil pump worn or mountings loose
Excessive oil consumption
m
mOverfilling
m mLeaking gaskets or drain plug washer
m mValve stem oil seals worn, damaged or missing after rebuild
m mValve stems and/or guides worn
m mPiston rings and/or bores worn
m mPiston oil return holes clogged
Oil contaminated with water
m
mExcessive cold running
m mLeaking head gasket
m mCracked block or head
Oil contaminated with fuel
m
mExcessive use of choke
m mWorn piston rings and/or bores
Unusual mechanical noises
m
mUnintentional mechanical contact (eg fan blade)
m mWorn drivebelt
m mWorn valvegear (tapping noises from top of engine) or incorrect
clearance
m mPeripheral component fault (generator, coolant pump)
m mWorn big-end bearings (regular heavy knocking, perhaps less under
load)
m mWorn main bearings (rumbling and knocking, perhaps worsening
under load)
m mSmall-end bushes or gudgeon pins worn (light metallic tapping)
m mPiston slap (most noticeable when engine cold)
m mWorn timing chain and gears (rattling from front of engine)
m mWorn crankshaft (knocking, rumbling and vibration)
1•36 All engines

2
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “No loss” with radiator and integral expansion tank. Electric cooling
fan, belt-driven coolant pump, thermostat on cylinder head
General
Radiator fan cuts in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 to 94ºC (194 to 201ºF)
Radiator fan switches off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
Thermostat opens:
903 cc engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
1116 cc and 1301 cc engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 to 87ºC (181 to 188.6ºF)
Fully open:
903 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100ºC (212ºF)
1116 cc and 1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95ºC (203ºF)
Expansion tank pressure cap rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.78 bar (11 lbf/in2)
Coolant
Capacity:
903 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 litre (8.1 pint)
1116 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0 litre (10.6 pint)
1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 litre (10.9 pint)
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ethylene glycol based antifreeze
Torque wrench settingsNm lbf ft
Temperature sender switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Coolant pump mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 25
Alternator adjuster and mountings nuts . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Chapter 2 Cooling and heating systems
For modifications, and information applicable to later models, see Supplement at end of manual
Coolant mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Coolant pump - removal, overhaul and refitting . . . . . . . . . . . . . . . . 9
Cooling system - draining, flushing and refilling . . . . . . . . . . . . . . . . 2
Cooling system sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Description and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Drivebelt - tensioning and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Fault finding - cooling and heating . . . . . . . . . . . . See end of ChapterHeater - dismantling, overhaul and reassembly . . . . . . . . . . . . . . . . 13
Heater unit - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Heating and ventilation system - description . . . . . . . . . . . . . . . . . . 11
Radiator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Radiator fan thermostatic switch - removal, checking and refitting . 5
Radiator fan - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 6
Thermostat - removal, testing and refitting . . . . . . . . . . . . . . . . . . . . 4
2•1
Specifications Contents
1 Description and
maintenance
1
1The cooling system consists of a
front-mounted radiator with built-in expansion
tank, a coolant pump (belt-driven from the
crankshaft pulley) and a thermostatically-
controlled electric cooling fan.
2In order to assist rapid warm-up, athermostat is located in a housing at the
left-hand end of the cylinder head. The hose
connections to the thermostat housing vary
according to model.
3The heater is supplied with coolant from the
engine and incorporates a matrix and blower
with the necessary controls.
4The throttle valve plate block of the
carburettor is coolant-heated as a means of
improving fuel atomisation.
5Maintenance is minimal as in theory no
coolant should ever be lost from theexpansion tank. Regularly check that the
coolant level is between 50.0 and 70.0 mm
(1.97 and 2.8 in) above the MIN mark on the
tank with the engine cold. The need for
regular topping up will indicate a leak
somewhere in the system. If one cannot be
found suspect an internal leak in the engine
although this is usually confirmed by a rise in
the engine oil level and water on the dipstick
(photo). Any topping-up should be done using
an antifreeze mixture (see Section 3), not plain
water.
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
54321

6Avoid unscrewing the expansion tank cap
when the engine is hot, but if this must be
done, cover the cap with a cloth to avoid
scalding by escaping steam.
7Periodically, check the condition of all
coolant hoses and tighten the clips.
2 Cooling system- draining,
flushing and refilling
1
1Set the heater temperature lever to
maximum.
2Unscrew the cap from the expansion tank.
3Disconnect the radiator bottom hose and
unscrew the cylinder block drain plug (1116
cc and 1301 cc engines) and allow the coolant
to drain. Refer to photo 29.21B, page 64.
4If the system is in good condition with no
sign of rust or dirt in the drained coolant, then
it may be refilled immediately. If the system
has been neglected and the antifreeze has notbeen regularly renewed and there is evidence
of rust and sediment in the drained liquid then
flush the system through with a cold water
hose.
5If the radiator should appear to be clogged,
it may be necessary to remove it (Section 7)
invert it and reverse flush it using a cold water
hose. If, after a reasonable period the water
still does not run clear, the radiator should be
flushed with a good proprietary cleaning
system. Extensive damage should be repaired
by a specialist or the unit exchanged for a
new or reconditioned radiator.
6Reconnect the bottom hose and screw in
the drain plug.
7Remove the plug (B) (Fig. 2.2) from the
bleed hole in the heater hose.
8Remove the plug (D) (Fig. 2.3) from the
bleed hole in the expansion tank.
9Pour antifreeze mixture slowly into the filler
neck of the expansion tank until it is seen to
come out of the expansion tank plug hole.
Screw in the plug.
10Add further coolant until it is seen todribble out of the hole in the heater hose.
Screw in the plug.
11Top up the expansion tank to the
specified level and screw on the tank cap.
12Start the engine and run it until the cooling
fan cuts in. Switch off, allow to cool and top
up if necessary to the specified mark on the
expansion tank.
3 Coolant mixtures
1In cold climates, antifreeze is needed for
two reasons. In extreme cases, if the coolant
in the engine freezes solid it could crack the
cylinder block or head. But also in cold
weather, with the circulation restricted by the
thermostat, and any warm water that is
getting to the radiator being at the top, the
bottom of the radiator could freeze, and so
block circulation completely, making the
coolant trapped in the engine boil.
2The antifreeze should be mixed in the
proportions advocated by the makers,
according to the climate. There are two levels
of protection. The first cuts risk of damage, as
the antifreeze goes mushy before freezing.
The second, valid all year round, is the
corrosion protection it offers - see below. The
normal proportion in a temperate climate to
provide maximum protection against freezing
and corrosion is 50% antifreeze and
50% water.
3Use only ethylene glycol based antifreeze
and preferably soft water.
4Antifreeze should be left in through the
summer. It has an important secondary
function, to act as an inhibitor against
corrosion. In the cooling system are many
different metals, in particular the aluminium of
the cylinder head. In contact with the coolant
this sets up electrolytic corrosion,
accentuated by any dirt in the system. This
corrosion can be catastrophically fast.
5After about two years, the effectiveness of
the antifreeze’s inhibitor is used up. It must
then be discarded, and the system refilled
with new coolant.
6In warm climates free from frost, an
2•2 Cooling and heating systems
Fig. 2.3 Plug (D) in expansion tank (Sec 2)Fig. 2.2 Plug (B) in heater hose (Sec 2)
1.5 Expansion tank cap
Fig. 2.1 Cooling system on 903 cc engine (Sec 1)

fluid. They are “sealed”. Liquid will get in, but
a thorough clean will be impracticable, and it
will be impossible to get new grease in.
17Check all the parts, get a new gland, two
new grommets, (1116 cc and 1301 cc) and a
new gasket. Scrape all deposits out of the
housing and off the impeller.
18To reassemble, start by inserting the new
grommets (1116 cc and 1301 cc) in the
grooves by each bearing. Fit the circlip to the
shaft, then the shouldered ring, bearings and
spacer. Fit the shaft and bearing assembly
into the cover. Fit the stop screw. Press on
the pulley.
19Fit the new gland (seal), seating it in its
location in the cover. Press the impeller onto
the shaft. The impeller must be put on part
way, and then the housing held in place to see
how far the impeller must go down the shaft
to give the correct clearance, which is 0.8 to
1.3 mm (0.03 to 0.05 in) as shown in Figs. 2.4
and 2.5.
20The impeller clearance can be checked
through the coolant passage in the side of the
pump.
21Refitting is a reversal of the removal
process, but use a new flange gasket and
tension the drivebelt as described in Section 8
(photo).
22Refill the cooling system.
10 Cooling system sensors
1A coolant temperature sender switch is
located in the cylinder head (above No. 1
spark plug) on 903 cc engines and adjacent to
No. 2 spark plug on 1116 cc and 1301 cc
engines.
2The switch operates the coolant
temperature gauge and an excessive
temperature warning lamp.
3On some models, a level sensor is screwed
into the side of the expansion tank. This
sensor consists of a pair of reed switches
within a capsule which are kept closed by the
strong magnetic flux generated by the
hydrostatic force inspired by the action of the
coolant against the float.
4If the coolant level drops then the magneticflux is weakened and the switches open.
5In the event of a fault developing, before
assuming that the cause is the sensor, check
all connecting wiring.
11 Heating and ventilation
system- description
1The heater is centrally mounted under the
facia and is of fresh air type.2Air is drawn in through the grille at the base
of the windscreen. It then passes through the
coolant heated matrix when it can then be
distributed through selective outlets
according to the setting of the control levers.
3A booster fan is provided for use when the
car is stationary or is travelling too slowly to
provide sufficient air ram effect.
4Fresh air outlets are provided at each end
and centrally on the facia panel.
12 Heater unit-
removal and refitting
1
1Drain the cooling system.
2Disconnect the heater hoses at the engine
compartment rear bulkhead.
3Working within the car under the facia
panel, disconnect the leads from the
heater blower by pulling the connecting plug
apart.
4If a radio is fitted, disconnect the
aerial, earth, speaker and power leads from
it.
Cooling and heating systems 2•5
Fig. 2.6 Checking impeller clearance
(Sec 9)9.21 Fitting coolant pump (1116 cc engine)
Fig. 2.7 Heater and ventilation system (Sec 11)
A Fresh air inlet flap
B Air distribution flap
C Coolant valveD Blower
E MatrixF Control levers
G Footwell air duct
2

Fault finding - cooling and heating systems
2•8 Cooling and heating systems
Overheating
m mInsufficient coolant in system
m mPump ineffective due to slack drivebelt
m mRadiator blocked either internally or externally
m mKinked or collapsed hose causing coolant flow restriction
m mThermostat not working properly
m mEngine out of tune
m mIgnition timing retarded or auto advance malfunction
m mCylinder head gasket blown
m mEngine not yet run-in
m mExhaust system partially blocked
m mEngine oil level too low
m mBrakes binding
Engine running too cool
m
mFaulty, incorrect or missing thermostat
Loss of coolant
m
mLoose hose clips
m mHoses perished or leaking
m mRadiator leaking
m mFiller/pressure cap defective
m mBlown cylinder head gasket
m mCracked cylinder block or head
Heater gives insufficient output
m
mEngine overcooled (see above)
m mHeater matrix blocked
m mHeater controls maladjusted or broken
m mHeater control valve jammed or otherwise
defective

7 Carburettor idle speed and
mixture- adjustment
4
1All carburettors have their mixture
adjustment set in production. The screw is
fitted with a tamperproof cap.
2Under normal circumstances, only the idle
speed screw need be adjusted to set the
engine idle speed to the specified level.
3Before attempting to adjust the idle speed
or mixture, it is important to have the ignition
and valve clearances correctly set and the
engine at normal operating temperature with
the air cleaner fitted.
4Where the mixture must be adjusted, prise
out the tamperproof plug and turn the mixture
screw in to weaken or out to enrich the
mixture until the engine runs smoothly without
any tendency to “hunt”.
5Ideally an exhaust gas analyser should be
used to make sure that the CO level is within
the specified range.
6Once the mixture has been correctly set,
re-adjust the idle speed screw.
8 Carburettor-
removal and refitting
2
1Remove the air cleaner.
2Disconnect the flow and return fuel hoses
from the carburettor and plug them.3Disconnect the coolant hoses from the
carburettor throttle valve plate block.
Provided the cooling system is cold and not
under pressure there should be almost no loss
of coolant. Tie the hoses up as high as
possible with a piece of wire.
4Disconnect the vacuum and vent hoses
from the carburettor.
5Disconnect the throttle and choke controls
from the carburettor.
6Unscrew the mounting flange nuts and lift
the carburettor from the intake manifold
(photo).
7Refitting is a reversal of removal. Use a new
flange gasket and make sure that the fuel
return hose is routed above the air cleaner
intake.
9 Carburettor
(Weber 32 ICEV 50/250/1)-
servicing and adjustment
4
1The carburettor top cover with float may be
removed without the need to withdraw the
carburettor from the manifold. The other
adjustments described will require removal of
the carburettor.
2Unscrew the filter plug from the top cover,
clean the filter screen and refit it.
3Extract the top cover fixing screws, lift the
cover and tilt it to unhook it from the
diaphragm capsule link rod.
4Access to the fuel inlet needle valve isobtained by carefully tapping out the float arm
pivot pin. Take care, the pivot pin pillars are
very brittle.
5Check that the needle valve body is tight
otherwise fuel can bypass the needle valve
and cause flooding.
Float adjustment
6Reassemble and check the float setting. Do
this by holding the top cover vertically so that
the float hangs down under its own weight.
Measure dimension (A) (Fig. 3.10) which
should be between 1 0.50 and 11.10 mm
(0.41 to 0.44 in) with the gasket in position. If
necessary, bend the float arm tab to adjust.
7Now check the float travel which should be
45.0 mm (1.77 in). If adjustment is required,
bend the end of the float arm.
Accelerator pump stroke
8Using a twist drill as a gauge, open the
throttle valve plate through 3.5 mm (0.138 in).
9Turn the nut on the accelerator pump rod
until it just makes contact with the pump
control lever.
Fast idle adjustment
10With the choke valve plate fully closed by
means of the control lever, the throttle valve
Fuel system 3•7
Fig. 3.9 Fuel return hose correctly located
(Sec 8)
8.6 Carburettor mounting flange nut8.2 Fuel hose at carburettor
Fig. 3.10 Float setting diagram (Weber 32 ICEV 50/250) (Sec 9)
A = 10.5 to 11.0 mm (0.41 to 0.44 in) B = 45.0 mm (1.77 in)Fig. 3.11 Accelerator pump setting diagram
(Weber 32 ICEV 50/250) (Sec 9)
X = 3.5 mm (0.138 in)
3