Rear FIAT PUNTO 1998 176 / 1.G Owner's Manual

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
require cutting with a sharp Knife to release
the sump.
Clean away all old gasket material. Refitting
5
Wwn refitting, a bead of RTV silicone nsiant gasket 3 mm in diameter should be applied lo the sump flange. Fit the sump, screw in tha fixing screws and tighten to the spscabed torque. Note the flange end fixing
nuts
(see illustrations).
6
'//ait one hour for the gasket compound to henjai before filling with engine oil. 7 Refit the flywheel housing cover plate and tohaust system front pipe.
8
lower the vehicle to the ground and fill the eng'rewith oil (see Chapter 1A). Check the oil
fevai
alter running the engine for a few minutes.

13 Oil
pump and pick-up tube - >>>
removal,
inspection and ^ refitting ^
Removal 1 Drain tho engine oil and remove the sump adsswibed in Section 12.
%
Unscrew and remove the oil filter cartridge .
(see
Chapter 1A|. 3 Remove the timing belt as described In
Section A.
4
Lock
the crankshaft against rotat>on either by tfacng a block of wood between a crankshaft wb and the inside of the crankcase, or by jjmning the flywheel starter ring gear with a
lutabfe
tool.
I3v8a Removing the oil pump pressure relief valve
12.5a Tightening a sump fixing screw
5 Unscrew and remove the crankshaft sprocket boll and take off the sprocket. If it is tight, use two screwdrivers to lever it off, or use a two or three-legged puller. 6 Unbolt and remove the oil pick-up/filter screen assembly. Note the sealing washer. 7 Extract the oil pump fixing bolts and withdraw the pump. Remove the gasket.
Inspection 8 The oil pump incorporates a pressure relief valve, which can be removed for examination by depressing the spring plunger and pulling out the keeper plate (see illustrations). 9 If pump wear Is suspected, check the gears in the following way. Extract the fixing screws and remove the rear cover plate. The screws are very tight, and will probably require the use of an impact screwdriver (see illustration).
pressure relief valve
12.5b Sump fixing screw and flange end fixing nut
10 Check the clearance between the outer gear and the pump housing using feeler blades. Check the gear endtloat by placing a straightedge across the pump body, and checking the gap between the straight-edge and gear face (see illustrations). If the clearances are outside the specified tolerance, renew the oil pump complete. 11 If the pump is unworn, refit the rear cover plate and tighten the screws fully. 12 Apply air pressure from a tyre pump to the oil pump oil ducts, to clear any sludge or other material. Prime the pump by pouhng clean engine oil into its inlet duct, at the same time turning the oil pump inner gear with the fingers. 13 Lever out the oil seal and drive a new one squarely into the oil pump casing (see illustrations). Lubricate the oil seal lips.
13.9 Using an impact screwdriver to remove the oil pump rear cover pfate screws
13,19s Measuring oil pump outer gear-to- 13.10b Measuring oil pump gear endtloat pump housing clearance

2B*4 DOHC (16-valve) petrol engine in-car repair procedures
4.8 Undo three bolts and romove tho crankshaft pulley from the sprocket
Crankshaft setting toot fabrication 7 To make Ihe crankshafl setting tools, four old spark plugs will be required, together with four lengths of dowel rod. The length of each dowel rod is not critical, bul It must be long enough to protrude about 100 mm above the top of the cylinder head extension when resting on top of a piston located half way down its bore. What is critical, however, is that all four do wo I rods must be exactly the same length. 8 Break off the ceramic upper section of each plug and remove the centre electrode and earth tip. The easiest way to do this is to mount each spark plug in a vice (attar removing the ceramic uppor plug section) and drill a hole down through ihe centre of the plug. The diameter of Ihe drill bit should be the same as Ihe diameter of Ihe dowol rod to be used. When finished you should have four spark plug bodies and four equal length dowel rods which will slide through the centre of the spark plugs.
3 Cylinder compression test
1 When engine performance is down, or it misfiring occurs which cannot be attnbuted to the Ignition or fuel systems, a compression test can provide diagnostic clues as to the engine's condition. If the lest is performed regularly, it can give warning of trouble bofore any other symptoms become apparent.
4.10 Undo the upper timing cover upper retaining bolt, and the rear retaining boll
4.9 Undo the retaining bolt in the centre of the lower timing cover
2 The engine must be fully warmed-up to normal operxrtrfjg temperature, the battery must be fully charged, and all the spark plugs muse be removed (Chapter 1A>. The aid of an assistant wilt also be required. 3 Disable the ignition system by discon-necting the LT wiring plugs to the Ignition coils. 4 Fit a compression tester to the No t cylinder spark plug hole • the type of tester which screws into the plug thread is to be preferred. 5 Have the assistant hold the throttle wide open, and crank the engine on the starter motor; after one or two revolutions, the compression pressure should build up to a maximum figure, and then stabilise. Record the h.ghest reading obtained 6 Repeat the test on the remaining cylinders, recording Ihe pressure in each. 7 All cylinders should produce very similar pressures; any excessive difference indicates Ihe existence of a fault. Note that the compression should build up quickly in a healthy engine; low compression on (he first stroke, followed by gradually increasing pressure on successive strokes, indicates worn piston rings. A low compression reading on the first stroke, which does not build up during successive strokes, indicates leaking valves or a blown head gasket (a cracked head could also be tho cause). 6 If the pressure in any cylinder is very low, carry out the following test to isolate the cause. Introduce a teaspoonful of dean oil into that cylinder through its spark plug hole and repeal the lest. 9 If the addition of oil temporarily improves the compression pressure, this indicates that bore or piston wear is responsible for the pressure loss. No improvement suggests that leaking or burnt valves, or a blown head gasket, may be to blame. 10 A low reading from two adjacent cylinders is almost certainly due to the head gasket having blown between Ihem; the presence of coolant in the engine oil will confirm this. 11 If one cylinder is about 20 percent lower than the others and the engine has a slightly rough idle, a worn camshaft lobe could be the cause. 12 On completion of the test, refit the spark plugs and reconnect the ignition LT wiring plug.
4 Timing belt and covers -removal and refitting §
General information 1 The luncUon of the timing belt Is to drive the camshafts and coolant pump. Should the bell slip or creak in service, the valve timing will be disturbed and piston-to-valve contact wiu occur, resulting in serious engine damage. 2 The timing belt should be renewed at the specified Intervals (see Chapter 1A), or earlier If It is contaminated with oil, or if it is at all noisy In operation (a scraping noise due to uneven wear}. 3 If the timing belt is being removed, it is
a
wise precaution to check the condition of the coolam pump at the same time (oheck for signs of coolant leakage). This may avoid the need to remove the timing belt again at a later stage, should the coolant pump fail. 4 Before carrying out this procedure, it will be necessary to obtain or fabricate suitable camshaft locking tools and piston positioning tools as described in Section 2. The procedures contained In this Section depict the use of the home-made alternative tools described in Section 2. which were fabricated In the Haynes workshop. If the manufacturers tools are being used instead, the procedures are virtually identical. Oo not attempt to remove the timing bell unless the special totfs or their alternatives are available.
Removal 5 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of Ihis manual). 6 Remove the auxiliary drivebelt(s) as described In Chapter 1A. 7 Remove the air cleaner, Inlet air duct and resonator as desenbed In Chapter 4B. 8 Undo the three bolts and remove the crankshaft pulley from the sprocket (see illustration). 9 Undo the retaining bolt In the centre of the lower liming cover (see illustration). 10 Undo tho uppor timing cover upper retaining bolt, and the rear retaining bolt located above the alternator (see illustration). 11 Release the crankshaft TDC sensor wiring from the clip on the upper timing cover, then withdraw the cover slightly and slide Ihe wiring plug and socket from the liming cover slot (see illustrations). 12 Release the TDC sensor wiring from the periphery ol the upper and fower timing covers and remove both covers (see Illustrations). 13 Free the accelerator inner cable from the throttle cam, remove the outer cable spring dip, then pull the outer cable out from its mounting bracket rubber grommet. 14 From the side of the throttle body, disconnect the wiring connectors from the

2B*5 DOHC (16-valve) petrol engine in-car repair procedures
4.11a Release the crankshaft TDC sensor wiring from the clip on the upper timing cover... throttle potentiometer and the Idle control stepper motor. Disconnect the coolant temperature sensor wiring connector located
in
the inlet manifold below the throttle body,
end
disconnect the brake servo vacuum hose. 15 Disconnect the wiring connectors for the fuel injector harness and the intake air temperature/pressure sensor, then fcconnect the fuel pressure regulator vacuum hose and the EVAP purge valve hose. 18 Undo the two bolts securing the plastic mlet manifold upper section to the lower section. Release the spark plug HT lead from the location groove in the manifold upper wctton, then lift the upper section, complete
»ith
throttle body, off the engine. Recover the 0-rngs from the manifold ports. 17 Unscrew the two bolts securing the fuel
4£1a Screw the spark plug bodies of the homo-made piston positioning tools into each spark plug hole ...
4.21b ... place a suitable washer or similar into the recess to keep the dowel rod vertical...
4.11b ... then slide the wiring plug and socket from the timing cover slot
rail assembly to the inlet manifold lower section, then carefully pull the Injectors from the manifold. Lift the fuel rail and Injector assembly, with fuel hoses still connected, and position it to one side. 16 Undo the bolts securing the engine management ECU mounting brackets to the body and move the ECU to one side without disconnecting the wiring connector. 19 Remove the spark plugs as described in Chapter 1A. 20 Unscrew the two sealing plugs from the front and rear of the cylinder head extension to enable the camshaft locking tools to be inserted. 21 Screw the spark plug bodies of the home-made piston positioning tools into each spark plug hole and insert the dowel rods into each body. To keep the dowel rods vertical, locate a suitable washer or similar over Ihe rod and into the recess at the top of the spark plug hole. In the photos shown here, an old valve stem oil seal housing was used but anything similar will suffice (see illustrations). 22 Using a socket on the crankshaft sprocket centre bolt, turn the crankshaft in the normal direction of rotation until all four dowel rods are protruding from the top of the cylinder head extension by the same amount. As the engine is turned, two of the rods will move up and two will move down until the position is reached where they are all at the same hoight. The best way to check this is to place a straight edge along the top of the rods and turn the crankshafl very slowly until the
4.21c ... then insert the dowel rods
4.12b ... and lower timing covers
straight edge contacts all four rods (see illustration). 23 When all four rods are at the same height, all the pistons will be at the mid-point of their stroke. Using a screwdriver or similar inserted into the front timing hole in the cylinder head extension, check that the timing slot in the exhaust camshaft is approximately aligned with the liming hole. If the camshaft slot cannot be felt, turn the crankshaft through one complete revolution and realign the dowel rods using the straight edge. Check again for the camshaft slot. Note that although the pistons can be at the mid-point of their stroke twice for each cycle of the engine, the camshaft slots will only be positioned correctly once per cycle. 24 With the pistons correctly set, it should now be possible to screw in the camshaft
4.22 Place a straight edge along the top of the rods and turn the crankshaft until the straight edge contacts ail four rods

2B*8 DOHC (16-valve) petrol engine in-car repair procedures
8.3a Disconnect the LT wiring plugs from the two Ignition coils ... 4 Dip the new oil seal in oil then offer it up to the oil pump casing making sure that the sealing Hps are facing inwards. 5 Using a suitable tubular drift, drive the oil seal squarely into the casing. Remove the adhesive tape, 8 Reftl the crankshaft sprocket and timing belt wrth reference to Sections 5 and
Rear (left-hand side) oil seal Note: The following paragraphs describe renewal of the rear oil seal leaving the housing in position. Refer to Chapter 20 for details of removing ihe housing. 7 Remove the flywheel as described In Section 11. 8 Using a suitable hooked Instrument, remove the oil seal from the rear oil seal
L •
~ 1 8.8a Lift the cylinder head extension slightly and insert the tools {shown with cylinder head removed for clarity)...
8.3b ... then unscrew the mounting bolts end romove the ignition colls housing taking care not to damage the surface of the crankshaft. 9 Clean the seating In the housing and the surface of Ihe crankshaft. Check the crankshaft for burrs which may damage the sealing lip ol Ihe new seal, and If necessary use a Tine file to remove them. 10 Dip the new seal In clean engine oil and carefully locate it over Ihe crankshaft rear flange making sure that it is the correct way round. 11 Progressively tap the oil seal into the housing keeping it square to prevent distortion. A block of wood Is useful for this purpose. 12 Refit the flywheel with reference to Section 11,
8 Cylinder head extension -removal and refitting ^
Removal 1 Remove the timing bolt as described in Soction A. 2 Identify the two HT leads for position then disconnect them from the coil HT terminals. 3 Disconnect the LT wiring plugs from the two ignition coils, then unscrew the mounting bolts and remove the ignition coils from the and of the cylinder head extension {see illustrations). A Undo the bolt and remove the resonator support bracket from Ihe top of the cylinder head extension,
8.8b ... thon remove the cylinder head extension
8.G Unscrew tho protective caps covering the cylinder head extension retaining bolts
5 Unscrew the protective caps covering the cylinder head extension retaining bolts (see Illustration). 6 To retain the cam followers in place as the cylinder head extension Is removed. Flat special tool No 1860988000 will bo required. This tool consists of two strips ol suitably slotted thin metal angle which sDp between the cylinder head extension and cylinder head mating faces as the extension Is lifted off. The tool holds the cam followers in place in the extension allowing the assembly to be withdrawn without fouling the Inlet and exhausl valves, The tools are refetJvety inexpensive and readily available from Fiat dealers. Suitable alternatives can be fabneated, If desired, usrnj thin metal angle strip cut to the dimensions shown (see Tool tip). 7 Progressively slacken and remove the boll$ securing the cylinder head extension to the cylinder head. 8 Lilt tho cylinder head extension up very slightly, keeping it square to the cylindei head. Slip the toots in place to hold the cam followers, then lift the extension off the cylinder head (see illustrations). Recover the gasket between the two assemblies. 9 Dismantling and Inspection procedures lor the cylinder head extension and camshafts are given in Section 9. Refitting 10 Ensure thai Ihe mating faces of the cylinder head and extension aro thorough^ cleaned, with all traces of old gasket removed, then locate a new gasket on Ihe cylinder head (see Illustration).
8.10 Locate a new gasket on the cylinder head
To make a cam follower retaining tool, obtain two lengths of 1hln metal angle and cut both to the dimensions (In mm) shown

DOHC (16-valve) petrol engine in-car repair procedures 2B*11
camshaft cover plate... 25 Locate the cam follower retaining tools in position and refit the cylinder head extension
as
described In Section 8.

10
Cylinder head - &
removal and
refitting S
Removal Note; The cylinder head bolts are of special
sekned
design and a Fiat tool should be
obtained
to unscrew them. A Ton key will not
JSt however
in practise It was found that a dose-httlng Alien key could be used as an itemative. 1 Drain the cooling system as described in Chapter 1A. 2 Remove the cylinder head extension as oescAbed
m
Section 8. 3 Disconnect the radiator hose from the thermostat housing on the left-hand end of
Ihe
cylinder head. 4 Disconnect the heater hose from the outlet
at the
rear of the cylinder head. 5 Disconnect the coolant temperature sensor md temperature gauge sensor wiring plugs
torn
the left-hand end of the cylinder head. 9 Undo the engine oil dipstick tube bracket retaining bolt and the two bolts securing the wing harness support clips to the inlet marriold lower section. 7 Undo Ihe retaining nuts and separate the ixhaust system front pipe from the exhaust manifold flange.
8
Check that nothing remains attached to the cinder head likely to impede removal. It Is assumed that the head will be removed complete with exhaust manifold and inlet manifold lower section. 9 Unscrew the cylinder head bolts half a turn K
e
time in the reverse order to that shown in (lustration 10.20a. When the bolts are free. «mwe them from their locations.. Id Lift the cylinder head from the block. If it is stuck tight rock the head to break the joint by mans of the manifolds. On no account drive
levers
into the gasket Joint, nor attempt to tap tf« head sideways, as it is located on positioning dowels. 11 Remove and discard the cylinder head gasket.
JK'
l^. 9.22b ... then apply RTV gasket sealant to the cover plate contact face 12 Refer to Chapter 20 for cylinder head dismantling and inspection procedures. Preparation for refitting 13 The mating faces of the cylinder head and cylinder block must be perfectly dean before refitting the head. Use a hard plastic or wooden scraper to remove all traces of gasket and carbon; also clean the piston crowns, Take particular care when cleaning the piston crowns as the soft aluminium alloy is easily damaged. Make sure that the carbon is not allowed to enter the oil and water passages -this Is particularly important for the lubncahon system, as carbon could block the oil supply to the engine's components. Using adhesive tape and paper, seal the water, oil and bolt holes in the cylinder block. To prevent carbon entering the gap between the pistons and bores, smear a little grease In the gap. After cleaning each piston, use a small brush to remove all traces of grease and carbon from the gap. then wipe away the remainder with a clean rag. Clean all the pistons in the same way. 14 Check the mating surfaces of the cylinder block and the cylinder head for nicks, deep scratches and other damage. If slight, they may be removed carefully with a file, but If excessive, machining may be the only alternative to renewal. If warpage of the cylinder head gasket surface Is suspected, use a straight-edge to check it for distortion. Refer to Part 0 of this Chapter if necessary. 15 Check the condition of the cylinder head bolts, and particularly their threads, whenever they are removed. Wash the bolts In a suitable
sequence
9.24 Lubricate the cam followers and place them in position in their respective bores solvent, and wipe them dry. Check each bolt for any sign of visible wear or damage, renewing them if necessary.
Refitting 18 Before refitting the assembled cylinder head, make sure that the head and block mating surfaces are perfectly clean, and that the bolt holes in the cylinder block have been mopped out to clear any oil, 17 The now gasket should not be removed from its nylon cover until required for use. Fit Ihe gasket dry, and make sure that the mating surfaces on the head and block are perfectly clean. 18 Place the gasket on the cylinder block so that the word ALTO can be read from above. 19 Lower the cylinder head onto the block so that it locates on the positioning dowel. 20 The cylinder head bolt threads must be clean and lightly lubricated. Screw the bolts in finger-tight then working progressively and in the sequence shown, lighten all the cylinder head bolts to the Stage 1 torquo setting given In the Specifications, using a torque wrench and a suitable socket. With all the bolts tightened to their Stage 1 setting, working again in the specified sequence, first angle-tighten the bolts through the specified Stage 2 angle, then again through the Stage 3 angle, using a socket and extension bar. It Is recommended that an angle-measuring gauge Is used during this stage ot tightening, to ensure accuracy (see Illustrations). 21 Reconnect the exhaust system front pipe to the manifold using a new flange gasket.
10.20b Tighten the cylinder head bolts to the Stago 1 torque setting ...

2C*2 Diesel engine in-car repair procedures
1 General information
Using this Chapter Chapter 2 is divided Into four Parts; A. 8, C and 0. Repair operations that cart be carried out with the engine in the vehicle are described In Part A, SOHC (B-valve) petrol engines. Part B, DOHC (16-valve) petrol engines and Part C. diesel engines, Part D covers the removal of the engine/transmission as a unit, and describes the engine dismantling and overhaul procedures. In Parts A. 8 and C. the assumption Is made that the engine is installed in Ihe vehicle, with all anciliaries connected If the engine has been removed for overhaul, the preliminary dismantling information which precedes each operation may be ignored.
Engine description Both normally aspirated (non-turbo) and turbocharged diesel engines are fitted to the Punto range. The engines together with their codes are given in the Specifications at the start of lhis Chapter. The engines are water-cooled, single-overhead camshaft. In-line lour cylinder units with cast-iron cylinder blocks and aluminium-alloy cylinder heads. The engine is mounted transversely at the front of the vehicle, with the transmission bolted to the left-hand side of the engine. The cylinder head carries the camshaft which is driven by a toothed timing belt. It also houses the inlet and exhaust valves which are closed by single coll valve springs and run in valve guides pressed into the cylinder head. The valves are operated by cam followers fitted over each valve, and the clearances are adjusted by shims positioned between the followers and the camshaft lobes. The camshaft is supported by four bearings • the end bearings are machined in the cylinder head and the remaining bearings have caps bolted to the cylinder head. The cylinder head contains integral oiiways which supply and lubricate the camshaft and followers and it also Incorporates renewable swirl chambers. The crankshaft Is supported by five main bearings, and endfloat Is controlled by a thrust bearing fitted on the rear main bearing. All diesel engines are fitted with a brake servo vacuum pump dnven from the left-hBnd end of the camshaft. Engine coolant is circulated by a pump, driven by the auxiliary drivebeit. For details of the cooling system refer to Chapter 3. Lubricant is circulated under pressure by a pump, driven from the front of the crankshaft. Oil is drawn from the sump through a strainer, and then forced through an externally-mounted, replaceable screw-on filter. From there, it is distributed to the cylinder head.
where il lubncates the camshaft journals and followers, and also to the crankcase, where it lubricates the main bearings, connecting rod big- and small-ends, gudgeon pins and cylinder bores. Oil jets are fitted to the base of each cylinder bore - these spray oil onto the underside of the pistons, lo Improve cooling. An oil cooler is also fitted to reduce the temp-erature of oil before it re-enters the engine.
Repair operations possible with the engine in the car The following work can be carried out with the engine in the can a) Compression pressure - testing b) Auxiliary drivebeit - removal and refitting (refer to Chapter rej c) Valve clearances • checking and adjustment (refer to Chapter 1B) d) Camshaft cover - removal and refitting e) Tim/ng belt and covers • removal and refitting 0 Timing belt tensioner and sprockets -removal and refitting g) Cylinder head - removal and refitting' h) Camshaft and cam followers - removal end refitting' I) Camshaft oil seal - renewal j) Crankshaft oil seals - renewal k) Flywheel • removal, inspection and refitting I) Engine mountings - inspection and renewal m)Sump • removal and refitting n) Oil pump and pick-up tube assembly -removal, inspection and refitting 'Cylinder head dismantling procedures are detalfed In Chapter 2D, with details of camshaft and cam follower removal. Note: It ts possible to remove the pistons and connecting rods (after removing the cylinder nead and sump) without removing the engine. However, this is not recommended. Work of this nature is more easily and thoroughly completed with the engine on tho bench as described in Chapter 2D.
2 Location of
TDC
on ^ No
1
cylinder ||
General information 1 The camshaft and fuel Injection pump are driven by the crankshaft, by means of sprockets and a timing belt. All three sprockets rotate in phase with each other and this provides the correct valve and injection pump timing as the engine rotates. When the timing bell is removed during servicing or repair, it is possible for the camshaft, injection pump and crankshaft to rotate independently of each other and the correct timing Is then lost.
2 It Location of TDC on cylinder No
1
6 Remove the air inlet ducting as described ft Chapter 4C, Section 2. 7 Remove the heater glow plugs with reference to Chapter 5C. Due to the high compression ratio of diesel engines this Is necessary to allow the engine to be turned by hand. 8 Unscrew the mounting bolts and move the coolant expansion tank to one side for access to the timing covers. Release the hose from the clips on Ihe camshaft cover. 9 Release the toggle clips and remove the upper timing cover (see illustration),
2.9 Removing the upper timing cover