belt FIAT UNO 1983 Service User Guide

8Fit the new belt. Start at the crankshaft
drive pulley and, taking care not to kink or
strain the belt, slip it over the camshaft pulley.
The camshaft may have to be turned slightly
to mesh the pulley with the teeth on the belt.
Fit the belt on the tensioner pulley last; if this
is difficult, do not lever or force the belt on,
recheck the belt (photo).
9Release the tensioner nut and rotate the
crankshaft through two complete revolutions.
Retighten the nut. The belt tension may be
checked by twisting it through 90º with the
finger and thumb. It should just turn through
this angle without undue force. Note: The
above procedure serves only as a rough guide
to setting the belt tension - having it checked
by a FIAT dealer at the earliest opportunity is
recommended.
10Refit the timing belt cover (photo). Fit and
tension the alternator drivebelt (Chapter 2,
Section 8).
29 Cylinder head-
removal and refitting
3
1Drain the cooling system (see Chapter 2).
2Disconnect the battery.
3Disconnect and plug the carburettor fuel
hoses.
4Disconnect the throttle and choke linkage
from the carburettor. 5Disconnect the HT leads from the spark
plugs.
6Disconnect the brake servo vacuum hose
from the intake manifold.
7Disconnect the coolant hoses from the
thermostat housing.
8Disconnect the crankcase ventilation
system hoses from the rocker cover and
carburettor.
9Unbolt and remove the timing belt cover.
10Release the timing belt tensioner pulley
bolt, then lever the pulley against the spring
plunger and retighten the bolt to retain the
tensioner pulley in the non-tensioned position.
Slip the belt from the camshaft sprocket.
11Disconnect the coolant hoses from the
carburettor and intake manifold.
12Disconnect the exhaust downpipes from
the manifold.
13If a crowfoot type wrench is available, the
cylinder head nuts and bolts can be removed
and the complete cylinder head camshaft
carrier assembly withdrawn (photo).
14If this type of wrench is not available
however, remove the carrier first as described
in Section 27.
15If a crowfoot is available, unscrew the
cylinder head nuts and bolts evenly and
progressively starting with the centre ones
and working towards both ends.
16Rock the cylinder head by gripping the
manifolds. Note: Do not insert a lever in
the gasket joint to prise the head from the
block.17Pull the head off the studs and remove it
to the bench. Remove and discard the old
cylinder head gasket.
18Unbolt and remove the hot air collecting
shield for the air cleaner from the exhaust
manifold. The exhaust and inlet manifolds can
now be unbolted. The carburettor may remain
on the inlet manifold.
19Overhaul and decarbonising of the
cylinder head is described in Section 39.
20Refitting is a reversal of the removal
process, but make sure the crankshaft and
camshaft timing marks are set as described in
Section 28 to avoid the valve heads digging
into the piston crowns when the head is
refitted.
21Always use new gaskets. The cylinder
1116 cc and 1301 cc engine 1•25
Fig. 1.29 Timing belt arrangement (Sec 28)
1 Camshaft sprocket
2 Tensioner pulley locknut
3 Timing mark on crankshaft front oil seal
retainer
4 Crankshaft sprocket
5 Crankshaft sprocket timing mark
6 Auxiliary shaft sprocket
7 Tensioner bracket bolt
8 Tensioner pulley
9 Timing belt
10 Tensioner bracket
11 Tensioner spring
28.8 Slipping timing belt onto tensioner
pulleyFig. 1.28 TDC marks (1) at front of engine
(Sec 28)
Fig. 1.30 Cylinder head bolt tightening
sequence (Sec 29)28.10 Tightening timing belt cover nut29.13 Using a crowfoot type wrench on a
cylinder head bolt
1

head gasket must be fitted (ALTO visible) so
that the oil pressure hole in the block is
central in the copper ringed cut-out in the
gasket (photos). Make sure that the gasket
surfaces on head and block are perfectly
clean and free from oil, otherwise the heat
sealing (polymerisation) process of the gasket
cannot take place.
22Tighten the cylinder head nuts and bolts
to the specified torque, in the sequence
shown in Fig. 1.30. Follow the procedure very
carefully owing to the special type (ASTADUR)
of gasket used which hardens in use. Always
keep a new cylinder head gasket in its
nylon cover until just before it is required for
use.
23Oil the cylinder head bolts and
washers and allow them to drain for thirty
minutes.
24Tighten the bolts in the following
stages:
Stage 1 20 Nm (15 lbf ft)
Stage 2 40 Nm (30 lbf ft)
Stage 3 Through 90º
Stage 4 Through 90º (photo)
Retightening the bolts after a running-in
mileage is not required.
25Fit the timing belt (Section 28).
26Check the valve clearances (Section 26)
after the camshaft carrier has been fitted
(Section 27).
27Bolt on the camshaft carrier cover.
28Reconnect all hoses, leads and controls.
29Reconnect the battery and refill the
cooling system.
30 Sump pan-
removal and refitting
1
1Position the car over an inspection pit or
raise the front wheels on ramps.
2Disconnect the battery.
3Drain the engine oil. Unbolt and remove the
flywheel housing lower cover plate.
4Unbolt the sump pan and remove it
together with its gasket.
5Refitting is a reversal of removal. Always
use a new gasket locating it on clean mating
flanges and tighten the fixing bolts evenly and
progressively (photo).
6Fill the engine with oil and reconnect the
battery.
31 Oil pump-
removal and refitting
1
1Remove the sump pan as described in the
preceding Section.
2Unbolt the oil pump and withdraw it
complete with driveshaft.
3Use a new gasket when refitting the pump
and prime the pump by pouring engine oil
through the pick-up filter screen (photo).
32 Pistons/connecting rod-
removal and refitting
3
1Remove the sump pan and the oil pump as
described in Sections 30 and 31.
1•26 1116 cc and 1301 cc engine
Fig. 1.31 Piston/connecting rod assembly
diagram (Sec 32)
1 Matching numbers
2 Gudgeon pin offset
3 Auxiliary shaft
Arrow indicates direction of rotation of
crankshaft viewed from timing belt end
29.24 Tightening a cylinder head bolt
through 90º using a protractor
31.3 Bolting on the oil pump30.5 Locating the sump pan gasket
29.21C Lowering cylinder onto block29.21B Cylinder head gasket in position -
cylinder block drain plug arrowed29.21A Cylinder head gasket top face
marking

from the suspension struts and then remove
the bolts which secure the hub carriers to the
U-clamps at the base of the suspension
struts.
23Pull the tops of the hub carriers down and
then outwards and push the driveshafts from
them.
24Unbolt the driveshaft inboard boot
retainers and then remove the driveshafts
from the transmission.
25Support the engine on a hoist or use a
trolley jack under the engine/transmission.
Remove the bottom mounting and then the
upper left and right-hand ones.
26Lower the power unit to the floor by
pushing it to the left-hand side to clear the
right-hand mounting bracket and then swivel
the gearbox towards the rear of the car.
Withdraw the engine/transmission from under
the car.
27External dirt and grease should now be
removed using paraffin and a stiff brush or a
water-soluble solvent.
28Unbolt and remove the engine mounting
brackets and the starter motor.
29Unbolt and remove the cover plate with
the gearchange ball stud strut from the lower
front face of the flywheel housing.
30With the engine resting squarely on its
sump pan, unscrew the flywheel housing
connecting bolts, noting the location of any
lifting lugs and hose and wiring clips.
31Support the weight of the transmission
and withdraw it in a straight line from the
engine.
36 Engine- dismantling (general)
Refer to Section 14, Part 2.
37 Engine ancillary components
- removal
Refer to Section 15, Part 2 and also remove
the intake manifold.
38 Engine-
complete dismantling
3
1Have the engine resting squarely and
supported securely on the work surface.
2Unbolt and remove the timing belt cover.
3Grip the now exposed timing belt with the
hands and loosen the camshaft sprocket.
4Release the timing belt tensioner pulley
centre bolt, then slip the belt from the pulley
and sprockets to remove it. Note which way
round the belt is fitted, usually so that the
lettering on the belt can be read from the
crankshaft pulley end of the engine.
5Remove the camshaft sprocket.6Unbolt and remove the camshaft timing belt
cover backing plate.
7Unbolt and remove the camshaft carrier
cover.
8Unbolt the camshaft carrier and lift it off
very slowly, at the same time pushing the cam
followers and their shims down with the
fingers securely onto their respective valve
springs. It is easy to remove the camshaft
carrier too quickly with some of the cam
followers stuck in it and as the carrier is lifted
away, the cam followers will fall out. If this
happens, the valve clearances will be upset as
the cam followers and shims cannot be
returned, with any certainty, to their original
positions. Keep the cam followers and shims
in their originally fitted order.
9Unscrew and remove the cylinder head
bolts and nuts, grip the manifold, rock the
head and remove the complete cylinder
head/manifold/carburettor assembly. Remove
and discard the cylinder head gasket.
10Unbolt the coolant pump from the side of
the cylinder block and remove it complete
with coolant distribution pipe. Remove the
crankcase breather.
11Remove the distributor/oil pump
driveshaft. This is simply carried out by
inserting a finger into the hole vacated by the
distributor and wedging it in the hole in the
end of the driveshaft. Lift the shaft out of
mesh with the auxiliary shaft. Where the
distributor is driven by the camshaft, a cover
plate retains the oil pump driveshaft in
position.
12Unbolt and remove the sprocket from the
end of the auxiliary shaft. The sprocket is held
to the shaft with a Woodruff key.
13Unbolt the auxiliary shaft retainer and
withdraw the shaft from the crankcase.
14Unscrew and remove the crankshaft
pulley nut. This is very tight and the flywheel
starter ring gear will have to be jammed with a
cold chisel or a suitably bent piece of steel to
prevent the crankshaft rotating.
15Withdraw the crankshaft sprocket, which
is located by the Woodruff key.
16Unbolt the front engine mounting bracket
from the cylinder block, together with the
timing belt cover screw anchor bush. Unbolt
and remove the timing belt tensioner pulley.
17Unscrew the flywheel securing bolts. Thestarter ring gear will again have to be jammed
to prevent the crankshaft rotating as the bolts
are unscrewed. Mark the flywheel position in
relation to the crankshaft mounting flange,
then remove it.
18Unbolt the front and rear crankshaft oil
seal retainer bolts from the crankcase and the
sump. Remove the oil seal retainers.
19Turn the engine on its side, extract the
remaining sump bolts and remove the sump.
If it is stuck, try tapping it gently with a
soft-faced hammer. If this fails, cut all round
the sump-to-gasket flange with a sharp knife.
Do not try prising with a large screwdriver; this
will only distort the sump mating flange.
20With the sump removed, unbolt and
remove the oil pump.
21Grip the oil pick-up pipe and twist or rock
it from its hole in the crankcase. It is an
interference fit in the hole.
22Remove the piston/connecting rods as
described in Section 32.
23Before unbolting the main bearing caps,
note that they are marked with one, two, three
or four notches. No. 5 main bearing cap is
unmarked. Note that the notches are nearer
the auxiliary shaft side.
24Unbolt and remove the main bearing
caps. If the bearing shells are to be used
again, tape them to their respective caps. The
bearing shell at the centre position is plain,
the others have a lubricating groove.
25Carefully, lift the crankshaft from the
crankcase, noting the thrust washers at No. 5
main bearing. These control the crankshaft
endfloat.
39 Cylinder head- dismantling
and decarbonising
4
1The operations are similar to those
described for the ohv engine in Section 17 in
respect of decarbonising and valve grinding.
2To remove a valve, use a valve spring
compressor to compress the first valve and
then extract the split collets (photo).
3Release the valve spring compressor.
4Withdraw the valve spring cap and the
double valve springs (photos).
5Remove the valve (photo).
1•28 1116 cc and 1301 cc engine
39.4A Valve spring cap39.2 Valve spring compressor and split
collets

6Remove the spring seat (photo).
7Discard the valve stem oil seal and fit a new
one (photo).
8Remove the remaining valves in a similar
way and keep the components in their
originally fitted sequence.
9Reassembly is a reversal of removal. Refit
the components to their original positions, but
renew the valve springs if their free length is
less than that of a new spring or if the
springs have been in operation for more than
80 000 km (50 000 miles).
10The original valve clearance adjusting
shims will no longer provide the correct
clearances if the valves have been ground in
or the seats recut. Only where dismantling of
a valve was carried out to renew a spring is
there any purpose in returning the shims to
their original locations. Try to obtain the loan
of eight thin shims from your dealer and insert
them into the tappets (cam followers) before
assembling the cam followers to the carrier,
where they should be retained with thick
grease (photo).
11Fit the camshaft carrier, complete with
cam followers and shims to the cylinder head.
12Adjust the valve clearances as described
in Section 26.
40 Examination and renovation
4
1The procedures are similar to those
described in Section 18 covering the
following:
Cylinder block and crankcase
Crankshaft and bearings
Pistons and piston rings
Flywheel
2The following additional items must also be
examined.
Oil pump
3Carefully, clamp the pump housing in a
vice, shaft downwards.
4Take off the pump cover, with the suction
pipe. This will release the oil pressure relief
valve inside. Also inside is a filter.
5Remove the internal cover plate.6Take out the driveshaft and the gears.
7Clean and examine all the parts. Measure
the clearances against the Specifications. The
end clearance is measured by putting a
straight-edge across the cover face.
8The oil pump should only need
replacements after very long mileage, when
the rest of the engine is showing great signs
of wear.
9The length of a new gear can be measured
against the old gear to see if a new gear will
restore the end clearance to the Specifica-
tions. Otherwise the housing must be
changed.
10The driven gear shaft is mounted in the
housing with an interference fit. If there is any
slackness, a new housing (which will come
with shaft fitted) must be used.
11The oil pump shares its drive with the
distributor.
Camshaft, cam followers and
shims
12The camshaft journals and cams should
be smooth, without grooves or scores.
13Wear in the camshaft carrier bearings can
only be rectified by renewal of the carrier.
14Cam follower wear is usually very small
and when they show slackness in their bores,
it is probably the light alloy of the camshaft
carrier which has worn.
15Always measure the thickness of the valve
clearance shims using a metric micrometer.
Any grooving or wear marks in the shims
should be rectified by renewal with ones of
similar thickness.
Auxiliary shaft
16The shaft journals, the fuel pump
eccentric, and the drivegear for the distributor
and oil pump should be smooth and shiny. If
not, the shaft will have to be renewed.
17The bushes should still be tight in the
cylinder block, their oil holes lined up with
those in the block.
18Measure the bearing clearance. If
excessive, the bushes will have to be
renewed. They are a press fit, and require
reaming with a special reamer after fitting.
This is a job best done by a Fiat agent with the
special tools.
19Ensure the new bushes are fitted with the
oil holes lined up.
20Also check the driven gear and its bush.
21It is recommended a new oil seal is fitted
in the endplate. Hold the shaft in a vice, and
remove the pulley. Fit the new oil seal in the
endplate, lips inwards.
Timing belt tensioner
22Check the bearing revolves smoothly and
freely, and has no play. Do not immerse it in
cleaning fluid, as it is partially sealed. Wipe
the outside, and then smear in some new
general purpose grease.
23The action of the spring will have been felt
when the belt was taken off. It should be
cleaned, and oiled, to prevent seizure through
dirt and rust.
24Note the circlip on the engine right-hand
mounting bracket. This retains the timing belt
tensioner plunger.
1116 cc and 1301 cc engine 1•29
39.6 Valve spring seat39.5 Removing a valve39.4B Double valve springs
39.10 Cam followers fitted to camshaft
carrier39.7 Valve stem oil seal
1

plate to the crankcase, using a new gasket
(photos).
11Fit the belt sprocket and partially tighten
its bolt. Then, using an oil filter strap wrench
or similar device to hold the sprocket against
rotation, tighten the bolt to the specified
torque. Take care not to damage the teeth of
the sprocket, which is of fibre construction
(photo).
Oil sump, sump pan and
breather
12Fit the oil drain pipe by tapping it into
place, squarely in its hole in the crankcase.
Tighten its retaining bolt (photo).
13Bolt up the oil pump, using a new gasket
at its mounting flange (photo).14Fit the sump (using a new gasket) and
tighten the securing screws to the specified
torque. Note the reinforcement washers
(photo).
15Insert the oil pump/driveshaft into the
distributor hole. This does not have to be
specially positioned as the distributor is
splined to the shaft and can be set by moving
its location in the splines (refer to Chapter 4)
(photo).
16Push the breather into its crankcase
recess and tighten its securing bolt (photos).Flywheel, crankshaft sprocket
and pulley
17Make sure that the flywheel-to-crankshaft
mounting flange surfaces are clean. Althoughthe bolt holes have unequal distances
between them, it is possible to fit the flywheel
in one of two alternative positions at 180º
difference. Therefore if the original flywheel is
being refitted, align the marks made before
removal.
18If a new flywheel is being fitted, or if
alignment marks were not made before
dismantling, set No. 1 position at TDC
(crankshaft front Woodruff key pointing
vertically). Fit the flywheel to its mounting
flange so that its timing dimple is uppermost
and in alignment with the relative position of
the TDC mark on the flywheel housing
inspection window.
19Insert the bolts and tighten them to the
specified torque, jamming the ring gear to
1116 cc and 1301 cc engine 1•31
42.11 Tightening camshaft sprocket bolt.
Note sprocket locking device42.10B Tightening auxiliary shaft end plate
bolt42.10A Auxiliary shaft end plate and
gasket
42.16B Crankcase breather and retaining
bolt42.16A Crankcase breather seal42.15 Fitting oil pump driveshaft
42.14 Tightening sump pan bolt42.13 Locating oil pump and gasket42.12 Tightening oil drain pipe bolt
1

prevent the flywheel turning. Fit the engine
endplate (photo).
20Fit the timing belt sprocket to the front
end of the crankshaft (photo).
21Fit the crankshaft pulley and the nut;
tighten it to the specified torque, again
jamming the starter ring gear to prevent the
crankshaft from rotating (photo).
Cylinder head
22Refitting is described in Section 29.
Camshaft carrier and camshaft
23Refitting is described in Section 27.
Timing belt and tensioner
24Refitting is described in Section 28, but
make sure that the belt cover rear plate is
bolted into position. If the engine mounting
bracket was removed, bolt it into positioncomplete with the tensioner plunger to
provide spring pressure to the belt pulley
(photos).
Valve clearances
25Check the valve clearances as described
in Section 26.
26Using new gaskets, bolt on the camshaft
carrier cover plate and the inlet and exhaust
manifolds using new gaskets. Fit the exhaust
manifold hot air collector plate (photo).
27Locate the engine rear plate on its dowels
by sliding it behind the flywheel (photo).
43 Engine ancillaries- refitting
1Bolt on the carburettor (Chapter 3). 2Fit the coolant pump and thermostat
housing (Chapter 2).
3Fit the alternator and tension the drivebelt
(Chapters 9 and 2).
4Fit the distributor (Chapter 4).
5Fit the fuel pump (Chapter 3).
6Fit the clutch (Chapter 5).
7Fit a new oil filter cartridge (Section 2 of this
Chapter).
44 Engine/transmission-
reconnection and refitting
3
1Offer the transmission to the engine making
sure that the clutch has been centralised as
described in Chapter 5 (photo).
1•32 1116 cc and 1301 cc engine
44.1 Offering transmission to engine42.27 Engine rear plate42.26 Tightening a camshaft carrier cover
nut
42.24C Engine mounting bracket with belt
tensioner plunger (arrowed)
42.24B Belt cover mounting stud42.24A Belt cover rear plate
42.21 Crankshaft pulley and nut42.20 Fitting crankshaft timing belt
sprocket42.19 Tightening flywheel bolts

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

inhibitor should be used. Again, a reputable
make giving full protection must be chosen
and renewed every two years. Inhibitors with
dyes are useful for finding leaks, and on some
makes the dye shows when the inhibiting
ability is finished.
4 Thermostat-
removal, testing and refitting
1
1The thermostat assembly is mounted on the
flywheel end of the cylinder block.
2Unfortunately, the thermostat/housing is a
complete unit and failure of the thermostat will
necessitate the purchase of the complete
component (photo).
3If the thermostat/housing is removed from
the engine, it can be suspended in water and
the water heated to check out its opening
temperature. Movement of the thermostat
valve can be observed to some extent
through the openings in the housing.
4When refitting, always use a new gasket at
its mounting face (photo).
5 Radiator fan thermostatic
switch- removal, checking
and refitting
1
1Drain the cooling system.
2If the thermostatic switch is being removed
because the fan is not operating and the
switch is suspect, check the fan fuse first,
before removing the switch.3To remove the switch, disconnect the leads
from the terminals and unscrew the switch.
4Connect a test bulb and battery across the
switch terminals and then immerse the
sensing part of the switch in a container of
water. Heat the water and, using a
thermometer, check the temperature of the
water when the bulb lights up, indicating the
switch is functioning. The switch should
operate at approximately 194ºF (90ºC). Allow
the water to cool and check that the switch
cuts out at 185ºF (85ºC). Renew a faulty
switch.
5Refitting of the switch is the reverse of the
removal procedure. Always fit a new O-ring on
the switch.
6 Radiator fan-
removal and refitting
1
1Disconnect the electrical leads from the
radiator fan motor.
2Unbolt the fan mounting struts from the
radiator and lift the complete assembly away.
3Refitting is a reversal of removal.
7 Radiator-
removal and refitting
1
1Drain the cooling system.
2Disconnect the electrical leads from the
radiator fan motor and thermostatic switch.3Disconnect the coolant hoses from the
radiator (photos).
4Release the clips from the top of the
radiator and withdraw the radiator complete
with fan from the engine compartment
(photos).
5The radiator is of combined plastic/metal
construction and any repair should be left to
specialists. In an emergency however, minor
leaks from the radiator may be cured by using
a radiator sealant with the radiator in situ.
6Refitting is a reversal of removal. Fill the
cooling system as described in Section 2.
8 Drivebelt-
tensioning and renewal
1
1The drivebelt for the alternator and coolant
pump is correctly tensioned if it deflects
through 10.0 mm (0.39 in) under moderate
thumb pressure at the mid point of the longest
run of the belt.
2To tighten the belt, release the mounting
and adjuster nuts on the alternator and prise
the alternator away from the engine. Tighten
the nuts when the belt is taut and then
re-check the tension as previously described.
Never over-tension a belt or the coolant pump
or alternator bearings may be damaged.
3Check the condition of the belt at regular
intervals. If frayed or cracked, renew it in the
following way.
4Release the alternator mounting and
adjuster nuts and push the alternator fully in
Cooling and heating systems 2•3
7.3A Radiator top hose4.4 Fitting thermostat housing
(1116 cc engine)4.2 Thermostat housing
7.4B Removing radiator/fan assembly7.4A Radiator fixing clip7.3B Radiator hose to thermostat housing
2

towards the engine. Slip the belt off the
pulleys. If this is difficult, turn the crankshaft
pulley using a spanner on its retaining nut
while pressing the belt over the edge of the
pulley rim. Use this method to fit the new belt
after first having engaged it with the coolant
pump and alternator pulley grooves.
5Tension the belt as previously described.
6The tension of a new belt should be
checked and adjusted after the first few
hundred miles of running.
9 Coolant pump- removal,
overhaul and refitting
4
Note: The design of the pump differs between
the 903 cc and the other two engines, but the
removal, overhaul and refitting operations are
essentially similar.
1To gain access to the coolant pump, open
the bonnet and remove the air cleaner.
2Slacken the alternator pivot and adjustment
nuts, push the alternator in towards the
engine and slip the drivebelt from the coolant
pump pulley. Unplug and remove the
alternator.3Drain the cooling system as previously
described.
4Disconnect the hoses from the coolant
pump, also the metal coolant transfer pipe
(photo).
5Unscrew and remove the coolant pump
securing bolts, and lift the pump from the
engine. Peel away and discard the old gasket.
6Clean away external dirt.
7The pump is likely to need overhaul for
worn or noisy bearings, or if the gland is
leaking. There is a drain hole between the
gland and the bearings to prevent
contamination of the bearing grease by leaks,
and possible damage to the bearings. Glandleaks are usually worse when the engine is not
running. Once started, a leak is likely to get
worse quickly, so should be dealt with soon.
Worn bearings are likely to be noted first due
to noise. To check them, the pulley should be
rocked firmly, when any free movement can
be felt despite the belt. But if the bearings are
noisy, yet there is not apparently any free
play, then the belt should be removed so the
pump can be rotated by hand to check the
smoothness of the bearings.
8Dismantling and assembly of the pump
requires the use of a press, and it is preferable
to fit a new pump.
9For those having the necessary facilities,
overhaul can be carried out as follows.
10Remove the retaining nuts and separate
the two halves of the pump.
11The pump shaft is an interference fit in the
impeller, bearings, and pulley boss. How the
pump is dismantled depends on whether only
the gland needs renewing or the bearings as
well, and what puller or press is available to
get everything apart.
12Assuming complete dismantling is
required, proceed as follows. Supporting it
close in at the boss, press the shaft out of the
pulley. Pull the impeller off the other end of
the shaft.
13Take out the bearing stop screw.
14From the impeller end, press the shaft
with the bearings out of the cover half of the
housing.
15Press the shaft out of the bearings, take
off the spacer, the circlip, and the shouldered
ring.
16Do not immerse the bearings in cleaning
2•4 Cooling and heating systems
1 Pump body
2 Pump cover
3 Impeller
4 Connector for hose from
outlet to pump
5 Seal
6 Gasket7 Circlip
8 Bearing shoulder washer
9 Inner seal
10 Inner bearing
11 Bearing retainment screw
and lock washer12 Spacer
13 Outer seal
14 Outer bearing
15 Lock washer
16 Pulley
17 Pump shaft
Fig. 2.5 Sectional views of 1116 cc and 1301 cc engine coolant pump (Sec 9)
Fig. 2.4 Sectional view of 903 cc engine coolant pump (Sec 9)
9.4 Coolant distribution tube at rear of
pump
1 Pump cover
2 Bearing spacer
3 Bearing stop screw
4 Cover nuts
5 Lifting bracket
6 Housing
7 Impeller
8 Gland (seal)
9 Circlip
10 Gasket
11 Shouldered ring
12 Grommets
13 Bearing
14 Pulley
15 Shaft