service interval FIAT PUNTO 1996 176 / 1.G Workshop Manual

Maintenance schedule - petrol models 1A.3
The maintenance Intervals in this manual are provided with the assumption that you, not the dealer, will be carrying out the work. These axe the minimum maintenance intervals recommended by us for vehicles driven daily.
if you wish to keep your vehicle in peak condition at all times, you may wish to perform some of these procedures more often. We encourage frequent maintenance, because it enhances the efficiency.
performance and resale value of your vehicle. When the vehicle Is new, it should be serviced by a factory-authorised dealer service department, In order to preserve the factory warranty.
Every 250 miles (400 km) or weekly Q Refer to Weekly checks
Every 5000 miles (7500 km) or
6 months - whichever comes first • Renew the engine oil and filter (Section 3)
Note: Frequent oil and fitter changes am good tor the engine. We recommend changing the oil at the mileage specified here, or at least
twice
a year if the mileage covered Is a less.
Every 10 000 miles (15 000 km) or
12 months - whichever comes first
In
addition to the items listed above, cany out the following: Q Check the operation of the brake warning lamp (Section 4) • Check the front brake pads for wear (Section 5) • Check the underbody and sealant for damage (Section 6) • Hose and fluid leak check (Section 7) • Check the condition of the exhaust system and its mountings (Section 8) • Check the condition of the driveshaft gaiters (Section 9) • Renew pollen filter (Section 10) • Check exhaust gas content and idle speed (Section 11) • Check the steering and suspension components for condition and security (Section 12)
Every 20 000 miles (30 000 km) or
2 years - whichever comes first
In
addition to the Items listed above, carry out the following: • Check and if necessary adjust the tension of the auxiliary drlvebelt(s) (Section 13) • Check the freeplay and height of the clutch pedal (Section 14) • Check and if necessary adjust the valve clearances (Section 15) HI Check and if necessary tighten inlet and exhaust manifold mountings (Section 16) • Renew the fuel filter (Section 17) D Renew the air filter element (Section 18) O Renew the spark plugs (Section 19) • Check the condition of the HT cables (Section 20) • Check the engine management system (Section 21) Q Lubricate all hinges and locks (Section 22) O Check the headlight beam adjustment (Section 23) • Carry out a road test (Section 24)
Every 30 000 miles (45 000 km) or
3 years - whichever comes first In addition to the items listed above, cany out the following: • Check the operation of the Lambda sensor (Section 25) • Check and if necessary top-up the manual transmission oil level (Section 26) • Check the operation of the evaporative loss system (Section 27) • Automatic transmission inner filter and fluid renewal (Section 28)
Every 40 000 miles (60 000 km) or
4 years - whichever comes first In addition to the items fisted above, carry out the following: • Check the rear brake shoes for wear (Section 29) • Renew the timing belt (Section 30)"
*Noto: Although the normal interval for timing belt renewal is 70 000 miles (105 000 km), It is strongly recommended that the belt Is renewed at 40 000 miles (60 000 km) on vehicles which are subjected to Intensive use, ie. malniy short Journeys or a let of stop-start driving. The actual belt renewal Interval Is therefore very much up to the individual owner, but bear in mind that severe engine damage will result if the belt breaks.
Every 60 000 miles (90 000 km) or
6 years - whichever comes first in addition to the items listed above, cany out the following: • Check the condition and operation of the crankcase emission control system (Section 31)
Every 80 000 miles (120 000 km) • Renew the manual transmission oil (Section 32)
Every 2 years
(regardless of mileage) • Renew the engine coolant (Section 33) • Renew the brake fluid (Section 34)

ia«6 Component location - petrol models
Rear underbody view (diesel model shown, petrol model similar)
1 Fuel
tank
2
Exhaust
tailpipe
and
silencer 3
Rear axle
4 Coll
springs
5
Rear
anti-mil
bar
6
Handbrake cables
T
Rear brake pressure
regulating
valve
S
Rear
shock absorber lower mountings
Maintenance procedures
1 Introduction
This Chapter is designed to help the home mechanic maintain his/her vehicle (or safety, eoonomy, long life and peak performance. The Chapter contains a master maintenance schedule, and Sections dealing specifically with each task in the schedule. Visual checks. ad}ustments, component renewal and other helpful Items are included. Refer to the accompanying Illustrations of the engine compartment and tho underside of the vehicle for the locations of the various components. Servicing your vehicle in accordance with ihe mlleaget/time maintenance schedule and the following Sections will provide a planned maintenance programme, which should result m a long and reliable service life. This Is a comprehensive plan, so maintaining some Items but not others at the specified service Intervals, will not produce the same results. As you service your vehicle, you will discover that many of the procedures can, and should, be grouped together, because of the particular procedure being performed, or because of the proximity of two otherwise-unrelated components to one another. For example, if the vehicle Is raised for any reason, the exhaust can be inspected at the same time as the suspension and steering components. The first step in this maintenance programme is to prepare yoursell before tne
actual work begins. Read through all the Sections relevant to the work to be carried out, then make a list and gather all the parts and tools required. If a problem is encountered, seek advice from a parts specialist, or a dealer service department.
2 Regular maintenance
1 If. from the time the vehicle is new, the routine maintenance schedule is followed closely, and frequent checks are made of fluid levels and high-wear items, as suggested throughout this manual, the engine will be kept in relatively good running condition, and the need for additional work will be minimised. 2 II is possible that there will be times when the engine rs running poorly due to the lack of regular maintenance. This is even more likely If a used vehicle, which has not received regular and frequent maintenance checks, is purchased. In such cases, additional work may need to be carried out. outside of the regular maintenance intervals. 3 If engine wear is suspected, a compression test (refer to the relevant Part of Chapter 2) will provide valuable information regarding the overall performance of the main internal components. Such a test can be used as a basis to decide on the extent of the work to bo carried out. II, for example, a compression test indicates serious internal engine wear, conventional maintenance as described in this
Chapter will not greatly improve the performance of the engine, and may prove a waste of time and money, unless extensive overhaul work is carried out first. 4 The following series of operations are those usually required to improve the performance of a generally poor-running engine:
Primary operations a) Cloan, inspect and test the battery
(See
Weekly checks), b) Check alt the engine-related fluids (See Weekly checks). c) Check the condition and tension of the auxiliary drivebeft($) (Section 13). d) Renew the spark plugs (Section 19). e) Inspect the ignition HT leads (Section 20). 0 Check the condition of the air filter, and renew if necessary (Section 18). g) Check the fuel filter (Section 17). h) Check tho condition of ell hoses, and check for fluid leaks (Sect/on 7). i) Check theexhaust
gas emissions (Section 11).
5 If the above operations do not prove fully effective, carry out the following secondary operations;
Secondary operations All items listed under Primary operations, plus the following; e) Check the charging system (Chapter 5K Section 4). b) Check the ignition system (Chapter 58). c) Check tho fuel system (see relevant Part of Chapter
4).
d) Renew the ignition HT leads (Section 20)

Maintenance schedule - diesel models 1B.3
The mamtenance intervals in this manual are provided with the assumption that you. reI ihe dealer, will be carrying out the work.
These
are the minimum maintenance intervals recommended by us for vehicles driven daily.
ff you wish to keep your vehicle In peak condition at all times, you may wish to perform some of these procedures more often. We encourage frequent maintenance, because it enhances the efficiency.
performance and resale value of your vehicle. When the vehicle Is new, it should be serviced by a factory-authorised dealer service department, in order to preserve the factory warranty.
Every 250 miles (400 km) or weekly O Refer to Weekly checks
Every 5000 miles (7500 km) or

6
months - whichever comes first • Renew the engine oil and filter (Section 3) P Drain any water from the fuel filter (Section 4)
Every 10 000 miles (15 000 km) or

12
months - whichever comes first ill addition lo tho Items listed above, cany out the following; D Check the operation of the brake warning lamp J (Section 5) Check the front brake pads for wear (Section 6) :-G Check the underbody and sealant for damage j" (Section 7) n Hose and fluid leak check (Section 8) 0 Check the condition of the exhaust system and its 1 mountings (Section 9) -D Check the condition of the driveshaft gaiters ", (Section 10) O Check and adjust the idle speed (Section 11) ;0 Renew (he fuel filter (Section 12) J] Renew the air filter element (Section 13) L) Renew the pollen filter (Section 14) •• Check the steering and suspension components • for condition and security (Section 15)
Every 20 000 miles (30 000 km) or

2
years - whichever comes first In addition to the Items listed above, cany out the following: (P Check and if necessary adjust the tension of the auxiliary drlvebeltfs) (Section 16) '• Check the freeplay and height of the clutch pedal " (Section 17) D Check and if necessary adjust the valve clearances (Section 18) Lubricate all hinges and locks (Section 19) • Check the headlight beam adjustment (Section 20) O Cany out a road test (Section 21)
Every 30 000 miles (45 000 km) or
3 years - whichever comes first In addition to the Items listed above, cany out the following: • Check and if necessary top-up the manual transmission oil level (Section 22)
Every 40 000 miles (60 000 km) or
4 years - whichever comes first In addition to the items listed above, cany out the following: • Check the rear brake shoes for wear (Section 23) • Renew the timing belt (Section 24)'
•Note: Although the normal interval for timing belt renewal is 70 000 miles (ids 000 km), it is strongly recommended that the belt Is renewed at 40 000 miles (60 000 km) on vehicles which are subjected to intensive use, le. mainly short Journeys or a lot of stop-start driving. The actual bait renewal interval Is therefore very much up to the Individual owner, but bear in mind that sevefe engine damage will result if the belt breaks.
Every 60 000 miles (90 000 km) or
6 years - whichever comes first In addition to the Items listed above, cany out the following: • Check the condition and operation of the emission control system components (Section 25)
Every 80 000 miles (120 000 km) • Renew the manual transmission oil (Section 26)
Every 2 years
(regardless of mileage) • Renew the engine coolant (Section 27) • Renew the brake fluid (Section 28)

Component location - diesel models ib-s
Rear underbody view - turbo diesel model
1
Fuel tank
2
Exhaust
tailpipe
and
silencer 3 Fear axle 4 Coil springs 5
Rear anti-roll bar
€
Handbrake cables
7
Rear brake pressure regulating valve
8
Rear shock
absorber
lower
mountings
Maintenance procedures
1 Introduction
This Chapter Is designed to help the home mechanic maintain his/her vehicle for safety, economy, long life and peak performance. The Chapter contains a master maintenance schedule, and Sections dealing specifically with each task in the schedule. Visual checks, adjustments, component renewal and other helpful items are included. Refer to the accompanying illustrations of the engine compartment and the underside of the vohicle for the locations of the various components. Servicing your vehicle in accordance with ihe mileage/time maintenance schedule and the following Sections will provide a planned maintenance programme, which should result in a long and reliable service life. This is a comprehensive plan, so maintaining some items but not others at the specified service internals, will not produce the same results. As you service your vehicle, you will ctecover that many of the procedures can. and should, be grouped together, because of the particular procedure being performed, or because of the proximity of two otherwise-unrelated components to one another. For example, if the vehicle is raised for any reason, the exhaust can be inspected at the same time as the suspension and steering components. The first step in this maintenance programme is to prepare yoursetf before the
actual work begins. Read through all the Sections relevant to the work to be carried out. then make a list and gather all the parts and tools required. If a problem is encountered, seek advice from a parts specialist, or a dealer service department.
2 Regular maintenance
1 If, from the time Ihe vehicle is new, the routine maintenance schedule is followed closely, and frequent checks are made of fluid levels and high-wear Items, as suggested throughout this manual, the engine wifl be kept in relatively good running condition, and the need for additional work will be minimised. 2 It is possible that there will be times when the engine is running poorly due to the lack of regular maintenance. This is even more likely if a used vehicle, which has not received regular and frequent maintenance checks, is purchased, in such cases, additions! work may need to be carried out, outside of the regular maintenance intervals. 3 If engine wear is suspected, a compression test {refer to Chapter 2C} will provide valuable information regarding the overall performance of the main internal components. Such a test can be used as a basis to decide on the extent of the work to be carried out. If, for example, a compression test indicates serious Internal engine wear, conventional maintenance as
described in this Chapter will not greatly improve the performance of the engine, and may prove a wa3te of time and money, unless extensive overhaul work Is carried out first. 4 The following series of operations are those usually required to Improve the performance of a generally poor-running engine:
Primary operations a,I Clean, Inspect and test the battery (See Weekly checks). b) Check all the engine-related fluids (See Weekly checks). c) Drain the water from the fuel filter (Section 4) d) Check the condition and tension of the auxiliary dnvebeft(s) (Section 16). e) Check the condition of the air fitter, and renew if necessary (Section 13). f) Check the condition of all hoses, and check for fluid leaks (Section 8). g) Check the engine idle speed setting {Section 11). h) Check the exhaust gas emissions (Section 25). 5 If the above operations do not prove fully effective, carry out the following secondary operations:
Secondary operations All items listed under Pnmary operations, plus the following: a) Check the charging system (Chapter 5A, Section 4). b) Renew the fuel filter (Section 12) and check the fuel system (see Chapter 4Q.

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
2.11 Unscrewing the crankshaft pulley bolts
6 Itae crankshaft sprocket Is also equipped •nth a timing mark - when this is aligned with 3relarence marking on the oil pump cover.
Hie
engine is set with cylinders No 1 and 4 at
TDC.
Note that it is the camshaft positioning that determines whether a cylinder is on its comcression or exhaust stroke.

Location
of TDC on cylinder No 1 7 Remove the air cleaner and ducting as descnbed in Chapter 4A or 4B. Remove the
spark
plug from No 1 cylinder as described in Chapter 1A. 8 Firmly apply the handbrake, then |ack up
the
front of the car and support it securely on iiia stands (see Jacking end vehicle support). 9 Remove the auxiliary drivebelt(s) as described in Chapter 1A. 10 Unbolt and remove the timing belt cover. Mole the bolt located at the bottom of the
coven
this can be easily overlooked. 11 Undo the three bolts and remove the crankshaft pulley from the sprocket (see {lustration). 12 Turn Ihe engine in its normal direction of rotation (using a socket or spanner on Ihe crankshaft sprocket centre bolt) until pressure an be felt at No
1
cylinder spark plug hole.
1 flfliyflg^ Remove all four spark plugs; "••"•1 this will make the engine HlNTl easier to turn; refer to Chapter 1A for details.
13 Continue turning the engine until the crahaft sprocket TDC timing mark is aligned with the mark on the cylinder head and the crankshaft sprocket timing mark is aligned with the mark on the oil pump cover (see ilustrations). 14 The engine is now set at TDC for No 1 cylinder on compression.
3 Cylinder compression test t ^
1 When engine performance Is down, or if misfiring occurs which cannot be attributed to tne ignition or fuei systems, a compression isst can provide diagnostic clues as to the
2.13a Camshaft sprocket and cylinder head TDC timing marks (arrowed) aligned -shown with timing belt removed engine's condition. II the test is performed regularly, it can give warning of trouble any other symptoms become apparent. 2 The engine must be fully warmed-up to normal operating temperature, the battery must be fufly charged, and all the spark plugs must be removed (Chapter 1A). The aid of an assistant will also be required. 3 Disable the ignition system by dis-connecting the LT wiring plug to the ignition coils. 4 Fit a compression tester to the No 1 cyl-inder 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 highest reading obtained. 6 Repeat the lest on the remaining cylinders, recording the pressure in each. 7 All cylinders should produce very similar pressures; any excessive difference indicates the existence of a fault. Note that the compression should build up quickly in a healthy engine; low compression on the 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 the cause). 8 If the pressure in any cylinder is very low. carry out the following test to isolate the cause. Introduce a teaspoonful of clean oil into that cylinder through its spark plug hole and repeat the test. 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 biown 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 them; the presence of coolant in the engine oil will confirm this. 11 If one cylinder is about 20 percent lower
2.13b Crankshaft sprocket and oil pump cover TDC timing marks (arrowed) aligned
than the others and Ihe 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 ^
Note: Fiat specify the use of a special timing belt fens/on measuring toot to correctly set tho timing belt tension. If access to this equipment cannot be obtained, an approximate setting can be achieved using the method described below. It the method described is used, the tension must be checked using the special tool at the earliest possible opportunity. Do not drive the vehicle over large distances, or use high engine speeds, until the belt tension is known fo be correct. Refer to a Fiat dealer foradvSce.
General information 1 The function of the timing belt is to drive Ihe camshaft and coolant pump. Should the belt slip or break In service, the valve timing will be disturbed and piston-to-valvo contact will occur, resulting in serious engine damage, 2 The timing belt should be renewed ai 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 coolant pump at the same time (check for signs of coolant leakage). This may avoid the need to remove the timing belt again at a later stage, should the coolant pump fall.
Removal 4 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support). Remove the right-hand front road wheel. 5 Remove the air cleaner and air ducting as described in Chapter 4A or 46. 6 Remove the auxiliary drivebelt(s) and the spark plugs as described in Chapter 1A.
2A

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

2C*2 Diesel engine in-car repair procedures
4.4a Unbolt the engine oil dipstick tube...
3 Cylinder compression test
Note: A compression tester specifically designed for diesef engines must be used for this test. 1 When engine performance Is down, or if misfiring occurs, 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 before any other symptoms become apparent. 2 A compression tester specifically Intended for diesel engines must be used, because of the higher pressures involved. The Ie6ter is connected to an adapler which screws Into the glow plug or injector hole. It is unlikely to be worthwhile buying such a tester for occasional use. but it may be possible to borrow or hire one • if not. have the test performed by a garage. 3 Unless specific instructions to the contrary are supplied with the tester, observe the following points: 9) The battery must bo in a good state of charge, the air titter must be clean, end the engine should be at normal operating temperature. b) AH the in/actors or glow plugs should be removed before starting the lest. If removing the injectors, also remove the flame shield washers, otherwise they may be blown out. c) The stop solenoid must be disconnected.
4.4b ... and remove it from the rubber grommet in the oil pump housing
fo prevent the engine from running or fuel from being discharged. 4 There is no need to hold the accelerator pedal down during the test, because the diesel engine air inlet is not throttled. 5 The cause of poor compression Is less easy to establish on a diesel engine than on a petrol one. The effect of introducing oil into the cylinders (wet testing) Is not conclusive, because there is a risk that the oil will sit in the recess on the piston crown, instead of passing to the rings. However the following can be used as a rough guide to diagnosis. 6 All cylinders should produce very similar pressures; a difference of more than 5 bars between any two cylinders Indicates the existence of a fault. Note that the compression should build up quickly In a healthy engine; low compression on the 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 hoad could also be the cause). 7 A low reading from two adjacent cylinders Is almost certainly due to the head gasket having blown between them: the presence of coolant In the engine oil will confirm this,
Leakdown test 8 A leakdown test measures the rate at which compressed air fed into the cylinder Is lost. It is an alternative to a compression test, and in many ways it is better, since the escaping air provides easy identification of where pressure loss is occurring (piston rings, valves or head gasket). 9 The equipment needed for leakdown testing is unlikely to be available to the home mechanic. If poor compression Is suspected, have the test performed by a suitably-equipped garage.
4 Timing belt and covers -removal
and
refitting
Note: Fiat specify the use of a spec/a/ timing belt tension measuring tool to correctly set the timing belt tension. If access to this equipment cannot be obtained, an approximate setting can be achieved using the method described below. If the method described is used, the tension must be checked using the special tool at the earliest possible opportunity. Do not drive the vehicle over large distances, or use high engine speeds, until the belt fens/on rs known to be correct. Refer to a Fiat dealer for advice.
General Information 1 The function of the timing belt is to drive the camshaft and fuel injection pump. Should the belt slip or break in service, the valve timing will be disturbed and piston-to-valve contact
will occur, resulting In serious engine damage. 2 The timing bolt should be renewed at the specified intervals (see Chapter 1B), or earlier If It is contaminated with oil. or If It is at al noisy In operation (a scraping noise due to uneven wear),
Removal 3 Set the engine at TDC on No 1 cylinder
as
described in Section 2. 4 Unbolt and remove tho engine oil dipstick tube and remove It from the rubber gromme! in the oil pump housing (see illustrations), 5 Before removing the timing belt check rts tension by turning the belt through 90" with finger and thumb midway between u* injection pump and camshaft sprockets. This will give you an Idea of the tension to apply when refitting, assuming the tension is already correct. Also note the position of the tensions pulley as a reference mark. 6 Release tho nut on the timing bea tensioner, move the tensioner pulley away from the belt and retlghten the nut to hold the pulley in the retracted position. 7 If the timing belt is to be re-used, use white paint or chalk to mark the direction of rotation on the belt (if markings do not already exist), then slip the belt off the camshaft, crankshaft and injection pump sprockets, and the idler and tensioner pulleys. Caution: If the belt appears to be In good condition and can be re-used, it fs essential that It Is refitted the same
wsy
round, otherwise accelerated wear will result, leading fo premature failure. 8 Check the timing belt carefully for any signs of uneven wear, splitting, or oil contamination. Pay particular attention to the roots of the teeth. Renew it if there is the slightest doutt about its condition. If the engine is undergoing an overhaul, renew the belt as a matter of course, regardless of its apparent conditio*. The cost of a new belt Is nothing compa/ed with the cost of repairs, should the belt freak in service. If signs of oil contamination art found, trace the source of the oil leak and rectify It. Wash down the engine timing baft area and all related components, to remove
sd
traces of oil.
Refitting 9 Before refitting, thoroughly clean the tknmg belt sprockets. Check that the tensioner and idler pulleys rotate freely, without any sign ol roughness. If necessary, renew them as described in Section 5. 10 Ensure that the crankshaft, camshaft and injection pump sprockets are still at their TDC positions as described In Section 2. 11 Engage the timing belt with the crankshaft sprocket, then locate it around the idler pufiey and onto the Injection pump sprocket making sure that it is kept taught. Continue to locate! around the camshaft sprocket and finally around Ihe tensioner pulley (see Illustration) Ensure the belt teeth seat correctly on Ihe sprockets.