1999 FIAT PUNTO cooling

Every 2 years - petrol models ia.i?
check, and if necessary top-up, the level in the expansion tank. Refit the cap on completion. Antifreeze mixture 22 The antifreeze should always be renewed at the specified Intervals. This is necessary not only to maintain the antifreeze properties, but also to prevent corrosion which would otherwise occur as the corrosion inhibitors
beoome
progressively less effective. 23 Always use an ethylene-glycol based antifreeze which Is suitable for use In mixed-metal cooling systems, The quantity of antifreeze and levels of protection are
Indicated In
the Specifications. 24 8efore adding antifreeze, the cooling system should be completely drained, preferably flushed, and all hoses checked for condition and security. 25 After filling with antifreeze, a label should
be attached
to the expansion tank, stating the type and concentration of antifreeze used, and the date installed. Any subsequent lopping-up should be made with the same
type and
concentration of antifreeze. 26 Do not use engine antifreeze In the windscreen/tailgate washer system, as it will
cause damage to the vehicle paintwork. A screenwash additive should be added to the washer system in the quantities stated on the bottle.
34 Brake fluid renewal | I

A


Warning: Brake hydraulic fluid can harm your eyes and damage painted surfaces, so use extreme caution when handling and pouring H. Do not use fluid that has been standing open for some t/me, as it absorbs moisture from the air. excess moisture can cause a dangerous ioss of braking effectiveness. 1 The procedure is similar to that for the bleeding of the hydraulic system as described in Chapter 9, except that the brake fluid reservoir should be emptied by siphoning, using a clean poultry baster or similar before starting, and allowance should be made for the old fluid to be expelled when bleeding a section of the circuit. 2 Working as described In Chapter 9, open the first bleed screw in the sequence, and
pump the brake pedal gently until nearly all the old fluid has bsen emptied from the master cylinder reservoir.
Old hydraulic fluid Is Invariably much darker In colour than the new, making It easy to distinguish the two.
3 Top-up to the MAX level with new fluid, and continue pumping until onty the new fluid remans in the reservoir, and new fluid can be seen emerging from the bleed screw. Tighten the screw, and top the reservoir level up to the MAX level line. 4 Work through all the remaining bleed screws in the sequence until new fluid can be seen at all of them. Be careful to keep the master cylinder reservoir topped-up to above the MIN level et all times, or air may enter the system and greatly increase the length of the task. 5 When the operation Is complete, check that all bleed screws are securely tightened, and that their dust caps are refitted. Wash off all traces of spilt fluid, and recheck the master cylinder reservoir fluid level. 6 Check the operation of the brakes before taking the car on the road.
1A

1B.2
Servicing specifications - diesel models
Lubricants and fluids Refer to end of Weekly checks on page 0*17
Capacities Engine oil (including filter) Non-turbo diesei engine 4.95 litres Turbo diesel engine 4.84 litres Cooling system 7.2 litres
Manual transmission Non-turbo diesel engine 2.37 litres Turbo diesei engine t .98 litres Power-assisted steering 0.65 litres
Fuel tank 47 litres Washer reservoir Without headlight washers 2.5 litres With headlight washers 7.0 litres
Engine Oil fitter Engine Idle speed: Non-turbo diesel engine Turbo diesel engine Auxiliary drivebelt tension ...... Valve clearances • engine cold: Inlet Exhaust
Champion C112
8l0«40rpm 900 ± 20 rpm 5.0 mm deflection midway between pulleys
0.30 mm * 0.05 mm 0.35 mm ± 0.05 mm
Cooling system Antifreeze mixture: 50% antifreeze Protection down to-35°C Note: Refer to antifreeze manufactuivr for latest recommendations.
Fuel system Air filter element: Non-turbo diesel engine (with Lucas/CAV Injection) Champion U611 Turbo diesel engine (with Bosch Injection) Champion U579 Fuel filter Champion L120
Brakes Brake pad lining minimum thickness 1-5 mm Brake shoe friction material minimum thickness 2.0 mm
Tyre pressures See end of Weekly checks on page 0*18
Torque wrench settings Fuel filter bracket to body ..... « Fuel filter to bracket i........ Manual transmission oil drain plug: Non-turbo diesel engine: Stage 1 Stage 2 Turbo diesel engine Manual transmission oil filler plug Roadwheel bolts
Nm Ibfft 18 13 24 18
12 9 Angle-tighten a further 180® 46 34 46 34

ib-4 Component location - diesel models
Underbonnet view - turbo diesel model
1 Engine oil filter
cap
2 Engine oil dipstick 3 Oil
tilter
4 Brake/clutch fluid
reservoir
5 Air cleaner
cover
6 Power steering pump 7 Coolant expansion
tank
8 Windscreen washer
fluid
reservoir 9 Front suspension strut upper mounting 10 Fuel filter/heater
housing
11
Fuel
injection pump 12 Battery 13 Power steering fluid reservoir
Front underbody view - turbo diesel model
1 Oil
fitter
2 Sump drain plug 3 Transmission drain plug 4 Electric cooling fan unit 5 Left-hand
driveshaft
6 Intermediate
shaft
7 Bight-hand
driveshaft
8 Front suspension lower arms 9 Front anti-roll
bar
10 Exhaust downpipe 11 Front brake calipers 12
Rear
engine mounting 13 Radiator bottom hose
expert22 fl/ia http://rutracker.org

Maintenance procedures - diesel models ib.?
Every 10 000 miles (15 000 km) or 12 months
5 Brake warning lamp operation check 1
1 With Ihe ignition Key inserted and turned to the MAR position, open the bonnet and depress the button on the top of the brake
fluid
reservoir cap (see illustration). I
As
the button is pressed, the brake warning
lamp
on the instrument panel should light. 3 If Ihe lamp fails to illuminate, check the operation of the level switch using a continuity taster, then refer to Chapter t2, Section 5,
and
check the Instrument panel bulb.
6 Front brake pad check ^
I
1 firmly apply Ihe handbrake, then jack up the front of the car and support it securely on arie stands (see Jacking and vehicle support). Remove the front roadwheels. 2 Using a steel rule, measure the thickness of
the
friction material of the brake pads on both brakes. This must not be less than 1.5 mm. Ctefc the thickness of the pad friction material through the hole on the front of the caliper
|see
lustration), 3
For a
comprehensive check, the brake pads should be removed and cleaned. The operation of the caliper can then also bo checked, and the condition of the brake disc iteeil can be fully examined on both sides. Refer to Chapter 9 for further Information. 4 If any pad's friction material Is worn to the specified thickness or less, all lour pads must to renewed as a set. Refer to Chapter 9. 5 On completion refit the roadwheels and lower the car to the ground.
7 Underbody sealant check f^
1 Jack up the front and rear of the car and support on axle stands (see Jacking and
vehicle
support). Alternatively position the car over
an
Inspection pit. 2 Check the complete underbody, wheel housings and side sills for corrosion and/or damage to the underbody sealant. If evident,
rapairi

8
Hose
and fluid leak check
1 Visually inspect the engine Joint faces. g3skets and seals for any signs of water or oil leaks. Pay particular attention to the areas
5.1 Depress tho button on the top of the brake fluid reservoir cap
around the camshaft cover, cylinder head, oil filter and sump joint faces. Bear in mind that, over a period of time, some very slight seepage from these areas is to be expected -what you are really looking for is any indication of a serious leak (see Haynes Hint). Should a teak be found, renew the offending gasket or oil seal by referring to the appropriate Chapters In this manual, 2 Also check the security and condition of all the engine-related pipes and hoses. Ensure thai all cable-ties or securing clips are In place and in good condition. Clips which are broken or missing can lead to chafing of the hoses, pipes or wiring, which could cause more serious problems In the future. 3 Carefully check the radiator hoses and heater hoses along their entire length. Renew any hose which is cracked, swollen or deteriorated. Cracks will show up better If the hose is squeezed. Pay close attention to the hose clips that secure the hoses to the cooling system components. Hose clips can pinch and puncture hoses, resulting in leaks. 4 Inspect all the cooling system components (hoses. )olnt faces etc.) for leaks. A leak in the cooling system will usually show up as white or rust-coloured deposits on the area adjoining the leak, Where any problems of this nature are found on system components, renew the component or gasket with reference to Chapter 3. 5 With the vehicle raised, inspect the fuel tank and filler neck for punctures, cracks and other damage, The connection between the filler neck and tank is especially critical. Sometimes a rubber filler neck or connecting hose will leak due to loose retaining clamps or deteriorated rubber. 6 Carefully check all rubber hoses and metal fuel lines leading away from the fuel tank. Check for loose connections, deteriorated hoses, crimped lines, and other damage. Pay particular attention to the vent pipes and hoses, which often loop up around the filler neck and can become blocked or crimped. Follow the lines to the front of the vehicle, carefully Inspecting them all the way. Renew damaged sections as necessary.
6.2 Check the thickness of the pad friction material through the hote on the front of the caliper
7 With the vehicle raised, check along the length of the underside for leaks from the metal brake lines, caused by damage or corrosion. 8 At each front brake caliper, check the area around the brake pipe unions and the bleed nipples for hydraulic fluid leakage, 9 Remove the front roadwheels and chock for fluid leakage from the area around the caliper piston seal. Check that the tip of the piston dust seal is correctly located in its groove. If it has been displaced, the brake caliper should be removed and overhauled as described in Chapter 9, to check for internal dirt Ingress or corrosion. 10 Check the area surrounding the master cylinder and vacuum servo unit for signs of corrosion, Insecurity or hydraulic fluid leakage. Examine the vacuum hose leading to the servo unit for signs of damage or chafing. 11 From within the engine compartment, check the security of all fuel hose attachments and pipe unions, and Inspect the fuel hoses and vacuum hoses for kinks, chafing and deterioration. 12 Where applicable, check the condition of the power steering fluid hoses and pipes.
A leak in the cooling system will usually show up as white or rust coloured deposits on the area adjoining the leak.

ib-8 Every 10 000 miles - diesel models
10.1 Checking the condition of a driveshaft gaiter
9 Exhaust system check
1 With the engine cold {at least an hour after tho vehicle has been driven), check ihe complete exhaust system from the engine to the end of the tailpipe. The exhaust system Is most easily checked with the vehicle raised on a hoist, or suitably supported on axle stands (see Jacking and vehicle support), so that the exhaust components are readily visible and accessible. 2 Check the exhaust pipes and connections for evidence of leaks, severe oorrosion and damage. Make sure that all brackets and mountings are In good condition, and that all relevant nuts and bolts are tight, Leakage at any of the joints or in other parts of tho system will usually show up as a black sooty stain in the vicinity ot the leak. 3 Rattles and other noises can often be Iracod to the exhaust system, especially the brackets and mountings. Try to move the pipes and silencers. If the components are able to come into contact with the body or
suspension parts, secure the system with new mountings. Otherwise separate the joints (if possible) and twist the pipes as necessary to provide additional clearance.
10 Driveshaft gaiter check
I
1 With the vehicle raised and securely supported on stands (see Jacking and vehicle support), turn the steering onto lull lock, then slowly rotate the roadwheel. Inspect the condition ol the outer constant velocity (CV) joint rubber gaiters, squeezing the gaiters to open out the folds. Check for signs ot cracking, splits or detenoration of the rubber, which may allow the grease to escape, and lead to water and grit entry into the joint. Also check the security and condition of the retaining clips. Repeat these checks on the Inner CV joints (see illustration). If any damage or deterioration is found, the gaiters should be renewed (see Chapter 8. Section 3). 2 At the same time, check the general condition of the CV joints themselves by first holding the driveshaft and attempting to rotate the wheel. Repeat this check by holding the inner joint and attempting to rotate the driveshaft. Any appreciable movement indicates wear in the joints, wear in Ihe driveshaft splines, or a loose driveshaft retaining nut.
11 Idle speed check and adjustment
1 The usual type of tachometer (rev counter), which works from ignition system pulses, cannot be used on diesel engines. A
diagnostic socket is provided for the use of Flat test equipment, but this will not normally be available to the home mechanic. If it Is not felt that adjusting the Idle speed by ear 19 satisfactory, It will be necessary to purchase or hire an appropriate tachometer, or else leave tho task to a Fiat dealer or other suitably equipped specialist, 2 Before making adjustments, warm up the engine to normal operating temperature. Make sure that the accelerator cable is correctly adjusted (see Chapter 4C). 3 The adjustment must be made with all electrical components (Including the cooling fan) switched off. It the fan comes on dunng the adjustment, wait until it switches off automatically before proceeding. 4 The idle adjustment screw Is located on the top of the fuel injection pump (see illustration). To adjust the idie speed loosen the locknut and turn the screw as required then tighten the locknut. 5 On completion switch off the engine.
12 Fuel filter renewal i
1 The fuel filter is located on the bulkhead in the engine compartment. An electrically-operated heater is located between the filter and tlw housing, 2 Position a suitable container under the fuel filler. Loosen tho bleed screw on the top of the filter, then disconnect the wiring from Ihe water sensor and loosen the water drain screw on the bottom of the filter. Allow the fuel to drain completely (see illustration). 3 Tighten the drain and bleed screws, then Use an oii niter strep to loosen the fuel filter {see illustration).
12.2 Loosening the bleed screw on the top of the fuel filter
11.4 fdie speed adjustment 1 Locknut 2 Adjustment screw

Maintenance procedures - diesel models 1B.13
Every 60 000 miles (90 000 km) or 6 years
Refer to Chapter 40. A full chock of the 26 Emissions control systems emissions control systems must be made by a check Fiat dealer.
Every 80 000 miles (120 000 km)
26 Manual transmission ,v->> oil renewal K
1 Pak the vehicle on a level surface, if possible over an inspection pit or on a ramp as the filer/level and drain plugs are accessed from
under the
engine compartment, ff necessary tack up Ihe vehicle and support on axle stands (see Jacking and
vehicle
support). 2
Wipe
clean the area around the filler/! a vol and vain plugs, which are situated on the front and bottom of the transmission (see Illustration}.
3 Using an Allen key, unscrew the fillor/level plug and clean it. 4 Position a suitable container beneath the transmission, then use the Allen key to unscrew the drain plug. Allow the oil to completely dram. 5 Wipe clean the drain plug then refit and tighten It. 6 Fill the transmission with the correct grade and quantity of oil, referring to Section 22 when checking the level. Refit and tighten the filler/level plug. 7 Where applicable lower the vehicle to the ground. 26.2 Transmission drain plug location (viewed from undor tho vohlcle)
Every 2 years (regardless of mileage)

27
Coolant renewal St I
Coo//ng system draining

A


Warning: Wait until the engine is coid before starting this procedure. Do not allow anti-fnue to come in contact with your skin, or with the painted surfaces of the vehicle.
Rinse
off spills immediately with plenty of water. Never leave antifreeze lying around fh an open container, or in a puddle in the driveway or on the garage floor. Children
and
pets are attracted by Its sweet smell,
bat
antifreeze can be fatal if ingested. 1 With the engine completely cold, cover the expansion tank cap with a wad of rag, and slowly turn the cap anti-clockwise to relieve the
pressure in the cooling system (a hissing sound will normally be heard). Wail until any pressure remaining in the system is released, then continue to turn the cap until it can be removed. 2 Position a suitable container beneath the radiator bottom hose connection, then release the retaining clip and ease the hose from the radiator stub (see Illustration), If the hose joint has not been disturbed for some time, it will be necessary to gently manipulate the hose to break the joint. Do not use excessive force, or the radiator stub could be damaged. Allow the coolant to drain into the container. 3 Certain models are fitted with cooling system bleed plugs, which should be opened to aid the draining process and help prevent airlocks. These are located on the heator Inlet hose and on the top right hand edge of the radiator (see Illustrations), ff the coolant has
been drained for a reason other than renewal, then provided It is clean and less than two years old, it can be re-used, though this is not recommended. 4 Once all the coolant has drained, reconnect the hose to the radiator and secure it in position with the retaining clip.
Cooling system flushing 5 If coolant renewal has been neglected, or if the antifreeze mixture has become diluted, then In time, the cooling system may gradually lose efficiency, as the coolant passages become restricted due to rust, scale deposits, and other sediment. The cooling system efficiency can be restored by flushing tho system clean. 6 The radiator should be (lushed independently of the engine, to avoid unnecessary contam-ination.
27.2 Disconnecting the radiator bottom hose to drain the coolant 27.3a Location of cooling system bleed plugs (arrowed) 27.3b Bleed screw located on the top right hand edge of the radiator

ib.14 Every 2 years - diesel models
Radiator flushing 7 To flush the radiator disconnect the top and bottom hoses and any other relevant hoses from the radiator, with reference to Chapter 3. 8 Insert a garden hose into the radiator top inlet. Direct a flow of dean water through the radiator, and continue Hushing until clean water emerges from the radiator bottom outlet. 9 II after a reasonable period, the water still does not run clear, the radiator can be flushed with a good proprietary cooling system cleaning agent. It is important that their manufacturer's instructions are followed carefully. If Ihe contamination is particularly bad, insert the hose in the radiator bottom outlet, and reverse-flush the radiator.
Engine flushing 10 To flush tho engine, remove the thermostat as described in Chapter 3. 11 With the bottom hose disconnected, direct a clean flow of water through the engine, and continue Hushing until clean water emerges from the radiator bottom hose. 12 On completion of flushing, refit the thermostat and reconnect the hose with reference to Chapter 3.
Cooling system filling 13 Before attempting to fill the cooling system, make sure that all hoses and clips are in good condition, and that the clips are tight. Note that an antifreeze mixture must be used all year round, to prevent corrosion of the engine components (see following sub* Section). 14 Remove the expansion tank filler cap. and fill the system by slowly pouring the coolant Into Ihe expansion tank to prevent airlocks from forming. Ensure that all bleed plugs/screws are open. 15 If the coolant is being renewed, begin by pouring in a couple of litres of water, followed by the correct quantity of antifreeze, then top* up with more water. 18 Once ihe level in the expansion tank starts to rise, squeeze the radiator top and bottom hoses to help expel any trapped air in
the system. Once all the air is expelled, top-up the coolant level to the MAX mark and refit the expansion tank cap. Close all bleed plugs. 17 Start Ihe engine and run il until it reaches normal operating temperature, then stop the engine and allow It to cool. 18 Check for leaks, particularly around disturbed components. Check the coolant level In the expansion tank, and top-up if necessary. Note that the system must be cold before an accurate level Is indicated In the expansion tank. If the expansion tank cap Is removed while the engine is still warm, cover the cap with a thick cloth, and unscrew the cap slowly to gradually relieve the system pressure (a hissing sound will normally be heard). Wait until any pressure remaining in the system Is released, then continue to turn the cap untH it can be removed.
Antifreeze mixture 19 The antifreeze should always be renewed at the specified intervals. This is necessary not only to maintain the antifreeze properties, but also to prevent corrosion which would otherwise occur as the corrosion Inhibitors become progressively less effective. 20 Always use an ethylene-glycol based antifreeze which is suitable for use in mixed-metal cooling systems. The quantity of antifreeze and levels of protection are indicated in the Specifications. 21 Before adding antifreeze, the cooling system should be complelely drained, preferably flushed, and all hoses checked for condition and security. 22 After filling with antifreeze, a label should be attached to the expansion tank, stating the type and concentration of antifreeze used, and the dale installed. Any subsequent topping-up should bs made with the same type and concentration of antifreeze. 23 Do not use engine antifreeze In the windscreen/tailgate washer system, as it will cause damage to the vehicle paintwork. A screenwash additive should be added to the washer system in the quantities stated on the bottle.
28 Brake fluid renewal

A


Warning: Brake hydraulic fluid can harm your eyas and damage painted surfaces, so use extreme caution when handling and pouring It. Do not use fluid that has been standing open for some time, as It absorbs moisture from the air. Excess moisture can causa a dangerous loss of braking effectiveness. 1 The procedure is similar to that for the bleeding of the hydraulic system as described In Chapter 9. except that the brake fluid reservoir should be emptied by siphoning, using a clean poultry baster or similar before starting, and allowance should be made for the old fluid to be expelled when bleeding a section of the circuit. 2 Working as described in Chapter 9, open Ihe first bleed screw in the sequence, and pump the brake pedal gently until nearly all the old fluid has been emptied from the master cylinder reservoir.
ffffTOgf Old hydraulic fluid Is
lifcjllitt*
Invariably much darker In [HINT] colour than the new, making /{easy to distinguish the two.
3 Top-up to the MAX level with new fluid, and continue pumping until only the new fluid remains in the reservoir, and new fluid can be seen emerging from (he bleed screw. Tighten the screw, and top the reservoir level up to Ihe MAX level line. 4 Work through all the remaining bleed screws In the sequence until new fluid can be seen al all of them. Be careful to keep the master cylinder reservoir topped-up 10 above the MIN level al all limes, or air may enter the system and greatly increase the length of the task. 5 When the operation is complete, check thai all bleed screws are securely tightened, and that their dust caps are refitted. Wash off ail traces of split fluid, and recheck the master cylinder reservoir fluid level. 6 Check the operation of the brakes before taking the car on the road,

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
Torque wrench settings Nm
IM
ft Camshaft cover 8 6 Camshaft sprocket 70 52 Cylinder head; Stage 1 30 22 Stage 2 Angle-lighten a further 90° Siege 3 Angle-tighten a further 90B Crankshaft sprocket centre bott 100 74 Engine mounting bolt: M10X1.25 69 44 MB 25 18 Engine mounting nut (M10x 1.25) 60 44 Flywheet/driveplate 44 32 Sump 10 7 Timing belt tensJoner 28 21
1 General information
Using this Chapter Chapter 2 is divided Into four Parts: A. 8. C and D. Repair operations that can be carried out with the engine in the vehicle are described in Part A. SOHC (8-valve) petrol engines, Part B. DOHC (18-valve) petrol engines and Part C, diesel engines. Part 0 covers the removal of the engine/transmission as a unit, and describes the engine dismantling and overhaul procedures. In Parts A, 9 and C, the assumption Is made lhat the engine is Installed in the vehicle, with sll ancillaries connected. If the engine has been removed for overhaul, the preliminary dismantling Information which precedes each operation may be ignored.
Engine description Throughout this Chapter, engines are identified by their capacities. A listing of all engines covered, together with their code letters, is given in the Specifications. The engines covered In this Part of Chapter 2 are water-cooled, single overhead camshaft, in-line four-cylinder units, with cast Iron cylinder Mocks and aluminium-alloy cylinder heads. All are mounted transversely at the front ot 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 and runs In three bearings. It also houses the inlet and exhaust valves, which are closed by single coil springs, and which run in guides pressed Into the cylinder head. The camshaft actuates the vatves directly via cam followers mounted in the cylinder head. Adjustment of the valve clearances is by means of shims located on top of the followers. The cylinder head contains Integral oitways which supply and lubricate the tappets. The crankshafl Is supported by five main bearings, and endftoat is controlled by a thrust bearing fitted to the upper section of the centre main bearing.
Engine coolant is circulated by 8 pump, driven by the timing belt. For details of the cooling system, refer to Chapter 3. Lubricant is circulated under pressure by a pump, driven from ihe 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 It lubricates the camshaft journals and tappets, and also to the crankcase, where il lubricates the main bearings, connecting rod big and smell-ends, gudgeon pins and cylinder bores. On 1242 cc engines, oil jets are fitted lo the base of each cylinder bore -these spray oil onto the underside of the pistons, to Improve cooling.
Repair operations possible with the engine in the car The following work can be carried out with the engine in the car a) Compression pressure - testing b) Auxiliary drivebelt - removal and refitting (refer to Chapter 1A) c) Vatve clearances - checking and adjustment (refer to Chapter I A) d) Camshaft cover - removal and refitting e) Timing belt and covens - removal and refitting f) Timing belt tensioner and sprockets -removal and refitting g) Cylinder head - removal and refitting' h) Camshaft and cam followers • removal and refitting' t) Camshaft oil seal - renews/ j) Crankshaft oil seals - renewal k) Flywheel/dnvepfate • removal, inspection and refitting l) Engine mountings - inspection and renewal m)Sump - removal and refitting n) Oil pump and pick-up tube assembly
•
removai. inspection and refitting *Cylinder head dismantling procedures are detailed In Chapter SO, with details of camshaft and cam follower removal. Note: It is possible to remove the pistons and connecting rods (after removing the cylinder head 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 the bench, as described In Chapter 2D.
2 Location of
TDC
on % No
1
cylinder
General Information 1 The camshaft Is driven by the crankshaft, by means of sprockets and a timing belt. Both sprockets rotate In phase with each other and this provides the correct valve timing as the engine rotates. When (he liming belt is removed during servioing or repair, it Is possible for the camshaft and crankshaft to rotate Independently of each other and the correct valve timing Is then lost. 2 The design of the engines covered In this Chapter are such lhat potentially damaging piston-to-valve contact may occur if the camshaft is rotated when any of the pistons are stationary at, or near, the top of their stroke. 3 For this reason it is important lhat Ihe correct phasing between the camshaft and crankshaft is preserved whilst the timing belt Is off the engine. This is achieved by setting the engine In a reference position (known as Top Dead Centre or TDC) before the timing belt Is removed and then preventing the camshaft and crankshaft from rotating until the belt is refitted. Similarly, if ths engine has been dismantled for overhaul, the engine can be set to TOC during reassembly to ensure that Ihe correct shaft phasing is restored. 4 TDC is the highest point In the cylinder that each piston reaches as the crankshaft turns. Each piston reaches TDC at Ihe end of the compression stroke and again at the end of the exhaust stroke. However, for the purpose of timing the ongine. TDC refers to the position of No 1 piston at the end of Its compression stroke. On ail engines In this manual, No 1 piston (and cylinder) Is at the timing belt end of the engine. 5 The camshaft sprocket Is equipped with a marking which, when aligned with a reference marking on the cylinder head, indicates that the camshaft is correctly positioned for cyl-inder No 1 al TDC on its compression stroke.