1998 FIAT PUNTO timing belt

2D*10 Engine removal and overhaul procedures
6.5s Prising out the feed stub of the camshaft lubricating pipe J) Flywheel (Chapter 2C). k) Clutch components (Chapter
6).
I) Cooling system components (Chapter
3).
Note: When removing trie external components from the engine, pay close attention to details that may be helpful or important during refitting. Note the fitted position of gaskets, seals, spacers, pins, washers, bolts, and other small components. 4 If you are obtaining a short engine (the engine cylinder block/crankcase, crankshaft, pistons and connecting rods, all fully assembled), then the cylinder head, sump, oil pump, timing belt (together with its tensloner and covers), coolant pump, thermostat housing, coolant outlet elbows, oil filter housing and where applicable oil cooler will also have to be removed. 5 If you are planning a full overhaul, the engine can be dismantled in the order given below: $) Ftywhaoi/drivoplate.
6.5d When removing the camshaft bearing caps, note the position of the (ong and short locating dowels
bearing/banjo union bolt b) Timing belt, sprockets, and tensioner. c) Inlet and exhaust manifolds. d) Cylinder head. e) Sump. f) Oil pump. g) Pistons and crankshaft.
6 Cylinder head - % dismantling, cleaning, inspection and reassembly ^
Note: Now and reconditioned cylinder heads are available from the manufacturer or engine overhaul specialists. Be aware that some specialist tools are required for the dismantling and inspection procedures, and new com-ponents may not be readily available. It may therefore be mors practical and economical for the home mechanic to purchase a reconditioned head, rather than dismantle, inspect and recondition the original head.
Dismantling Note: On 8-valve petrol engines and diesel engines, the camshaft and cam followers are /oca fed In the cylinder head assembly and the relevant dismantling and reassembly procedures are contained in this Section. On 1$-valve petrol engines, the camshafts and cam followers are /oca fed In a separate housing (cylinder head extension) which is bo/fed fo the top of the cylinder head. All procedures relating to the camshafts and cam followers on 16-valve engines are therefore contained in Chapter 2B. Proceed fo paragraph 15 for cylinder head dismantling
6.8a Unscrew and remove the bolts from the thermostat housing, noting the location of the bracket
6.5c Removing the camshaft lubricating pipe procedures on /6-vafve engines, and ignore any references to camshafts, cam followers and oil seals in the paragraphs that follow. 1 Remove the cylinder head as described in Part A. B or C of this Chapter (as applicable). 2 If not already done, remove the inlet and exhaust manifolds with reference to the relevant Part of Chapter 4. Also remove the spark plugs, glow plugs and injectors as applicable. 3 Remove the camshaft sprocket with reference to Chapter 2A or 2C. Petrol engines 4 Mark the positions of the camshaft bearing caps, numbering them from the timing end. 5 Unbolt and remove the lubrication pipe (prise the oil feed stub out with a screwdriver). Unscrew the remaining bolts and take off the bearing caps (see illustrations). 6 Lift the camshaft carefully from the cylinder head, checking lhat the valve clearance shims and cam followers are not withdrawn by the adhesion of the oil (see Illustration). 7 Remove the shims and cam followers, but keep them In their originally fitted order. Diesel engines 8 Unbolt the thermostat housing and gasket, and vacuum pump from the left-hand end of the cylinder head. Also if necessary unbolt the coolant cover and gasket from the right-hand end of the head. Note the location of brackets (see illustrations) 9 Using a soft metal drift, carefully lap out the left-hand side mount and recover the gasket (soe illustrations). 10 At tho timing bait end of the cylinder head.
6.8b Removing the thermostat housing ... 6.6 Removing the camshaft

2D*10 Engine removal and overhaul procedures

V.
^
•
• - >v
4L

6.8c ... and gasket
unscrew the bolts securing the right-hand Side mount to the head. Carefully tap out the right-hand side mount and recover the gasket (see illustrations). 11 Mark the positions of the camshaft bearing
6.10a Removing tho camshaft right-hand side mount...
6.12b ... and remove the bearing caps
6.8d Unscrew the vacuum pump mounting nuts noting the location of the bracket
caps, numbering from the timing belt end. 12 Progressively unscrew the bearing cap nuts then take off the bearing caps. Note the location dowels on the mounting studs (sae Illustrations).
6.12c The camshaft mounting studs incorporate location dowels
6.8e Removing the vacuum pump
13 Lift the camshaft towards the timing end. then remove it from the cylinder head (see illustration). Make sure the valve clearance shims and cam followers are not withdrawn by the adhesion of the oil.
6.13 Removing the camshaft from the cylinder head
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2D*10 Engine removal and overhaul procedures
6,14a Removing the shims... 6.14b ... and cam followers 6.16a Removing the upper spring seat...
14 Remove Ihe shims and cam followers, but keep them In their onginally fitted order (see illustrations) All engines 15 Stand the cylinder head on its end. Using a valve spring compressor, compress each valve spring in turn, extracting the split collets when the upper valve spring seat has been pushed far enough down the valve stem to free them. If the spring seat sticks, lightly lap Ihe upper |aw of the spring compressor with a hammer to free It. 16 Release tho valve spnng compressor and remove the upper spring seat, valve spring and lower spring seat (see illustrations) 17 Withdraw the valve from the head gasket side of the cylinder head, then use a pair of pliers to extract the valve stem oil seal from the top of the guide (see illustrations). If the
valve slicks In the guide, carefully deburr the end face wilh fine abrasive paper. Repeat this process for the remaining valves. 18 On diesel engines, if Ihe swiri chambers are badly coked or burned and are in need of renewal, they may be removed by unscrewing the retaining collars and carefully tapping them out from the combustion chamber side. Recover the washers and keep them identified for position (see illustration). 19 It is essential that each valve is stored together with Its collets, retainer, spring, and spring seat. The valves should also be kept in (heir correct sequence, unless they are so badly worn that they are to be renewed. If they are going to be kepi and used again, place each valve assembly in a labelled polythene bag or similar small container (see Illustration). Note that No 1 valve is at the timing belt end of Ihe engine.
Cleaning 20 Using a suitable degreasing agent, remove all traces of oil deposits from the cylinder head, paying particular attention to tho journal bearings, cam follower bores, valve guides and oilways. as applicable. Scrape off any traces ot old gasket from the mating surfaces, taking care not to score or gouge them. If using emery paper, do not use a grade of (ess than 100. Turn the head over and using a blunt blade, scrape any carbon deposits from the combustion chambers and ports. Caution: Do not erode the seeling surface of tho valve seat. 21 Finally, wash the entire head casting with a suitable solvent to remove the remaining debns. 22 Clean the valve heads and stems using 8 fine wire brush. If the valve is heavily coked,
5.18 Swirl chamber retaining collar (diesel engine) 6.19 Keep groups of components together in labelled bags or boxes

2D*10 Engine removal and overhaul procedures
7.13 Positioning of piston rings (petrol engine) 11 Scrape away all traces of carbon from the top of the piston. A hand-held wire brush (or a piece of fine emery cloth) can be used, once the majority ot the deposits have been scraped away. 12 Remove the carbon from the ring grooves In the piston, using an old ring. Break the ring in half to do this (be careful not to cut your fingers - piston rings are sharp). Be careful to remove only the carbon deposits • do not remove any metal, end do not nick or scratch the sides of the ring grooves. 13 Once the deposits have been removed, clean the piston/connecting rod assembly with paraffin or o suitable solvent, and dry thoroughly. Make sure that the oil return holes In the ring grooves are clear. Fit the rings to their respective grooves meking sure they are positioned the correct way round where applicable (see illustration). 14 If the pistons and cylinder bores are not
7.22 Prising out the gudgeon pin retaining circilps damagea or worn excessively, and if the cylinder block does not need to be rebored. the original pistons can be refitted. Normal piston wear shows up as even vertical wear on the piston thrust surfaces, and slight looseness of the top ring In its groove. New piston rings should always be used when the engine is reassembled. 15 Carefully inspect each piston for cracks around the skirt, around the gudgeon pin holes, and at the piston nng lands (between the ring grooves). 16 Look for scoring and scuffing on the ptston skirt, holes in the piston crown, and burned areas at the edge of the crown. If the skirt is scored or scuffed, the engine may have been suffering from overheating, end/or abnormal combustion which caused excessively high operating temperatures. The cooling and lubrication systems should be checked thoroughly. Scorch marks on the sides of the pistons show that blow-by has occurred. A hole in the piston crown, or burned areas at the edge of the piston crown, Indicates that abnormal combustion has been occurring. If any of the above problems exist, the causes must be investigated and corrected, or the
7.26a Piston to connecting rod assembly (petrol engine) 1 Piston grade (A) end directional arrow on piston crown (towards timing belt end) 2 Connecting rod/cap matching numbers 3 Gudgeon pin offset in piston (0.9 to 1.1 mm) Arrow indicates direction of crankshaft rotation
7.26b Piston to connecting rod assembly (diesel engine) 1 Piston crown
damage will occur again. The causes may Include Incorrect Ignition/injection pump timing, or a faulty injector (as applicable). 17 Corrosion of the piston, in the form ol pitting, indicates that coolant has been leaking into the combustion chamber and/or the crankcase. Again, the cause must be corrected, or the problem may persist In the rebuilt engine. 16 Examine each connecting rod carefully for signs of damage, such as cracks around the big-end and small-end bearings. Check that the rod is not bent or distorted, Damage is highly unlikely, unless the engine has been seized or badly overheated. Detailed checking of the connecting rod assembly can only be earned out by an engine repair specialist with the necessary equipment. 19 Although not essential. It is highly recommended that the big-end cap bolts are renewed as a complete set prior lo refitting. 20 On petrol engines piston and/or con-necting rod renewal should be entrusted to an engine repair specialist, who will have the necessary tooling to remove and install the interference fit gudgeon pins. 21 On diesel engines, the gudgeon pins are of the floating type, secured in position by two circlips. On these engines, the pistons and connecting rods can be separated as follows. 22 Using a small fiat-bladed screwdriver, prise out ihe circlips, and push out the gudgeon pin (see illustration). Identify the piston and rod to ensure correct reassembly. Discard the circlips - new ones must be used on refitting. 23 Examine the gudgeon pin and connecting rod small-end bearing bush for signs of wear or damage. Bush renewal should be entrusted to an engine overhaul specialist. 24 The connecting rods themselves should not be In need of renewal, unless seizure or some other major mechanical failure has occurred. Check the alignment of the connecting rods visually, and if the rods are not straight, take ihem to an engine overhaul specialist for a more detailed check. 25 Examine all components, and obtain any new parts as necessary. If new pistons are purchased, they will be supplied complete with gudgeon pins and circlips. 26 On reassembly position the piston on the connecting rod as shown (see Illustrations),
Injection pump location Connecting rod/cap matching numbers 7.28c Piston crown on diesel engines

Apply a smear of clean engine oil to the gudgeon pin. Slide it Into the piston and through the connecting rod small-end. Check that the piston pivots freely on the rod. then secure the gudgeon pin in position with two new circlips. Ensure that each circlip is correctly located In Its groove in the piston.
Refitting and big-end bearing running ciearance check 27 Prior to refitting the piston/connecting rod assemblies, it Is recommended that the big-end bearing running clearance is checked as follows. Big-end bearing running clearance check 28 Clean the backs of the bearing shells, and the bearing locations in both the connecting rod and bearing cap. 29 Press the bearing shells into their locations, ensuring that the tab on each shell engages in the notch In the connecting rod and cap. Take care not to touch any shell's bearing surface with your fingers. If the onginal bearing shells are being used for the check, ensure that they are refitted in their original locations. The clearance can be checked in either of two ways. 30 One method is to refit the big-end bearing cap to Ihe connecting rod, ensuring that they are litted the correct way around, with the bearing shells in place. Wilh the cap retaining bolls correctly tightened, use an internal micrometer or vernier caliper to measure the internal diameter of each assembled pair of bearing shells. If the diameter of each corresponding crankshaft journal is measured and Ihen subtracted from the bearing internal diameter, the result will be the big-end beanng running clearance. 31 The second, and more accurate method is to use a product called Plasligauge. Ensure that the bearing shells are correctly fitted then place a strand of Plastlgauge on each (cleaned) crankpin journal. 32 Refit the (clean) piston/connecting rod assemblies to the crankshaft, and refit the bg-end bearing caps, using the marks made or noted on removal to ensure that they are fitted the correct way around. 33 Tighten the beanng cap bolts taking care not to disturb the Plastlgauge or rotate the connecting rod dunng the tightening sequence. 34 Dismantle the assemblies without rotating the connecting rods. Use the scale pnnted on the Plastigauge envelope to obtain the big-end bearing running clearance. 35 If the clearance is significantly different from that expected, the bearing shells may be Ihe wrong size (or excessively worn. If the original shells are being re-used). Make sure mat no dirt or oil was trapped between Ihe bearing shells and the caps or block when the clearance was measured. If the Plastigauge was wider al one end than at the other, the crankshaft journal may be tapered.
2D*10 Engine removal and overhaul procedures
7.40a The arrow on the piston crown must point towards the timing belt end of the engine (petrol engine) 36 On completion, carefully scrape away all traces of the Plastigauge material from the crankshaft and bearing shells. Use your fingernail, or some other object which is unlikely to score the beanng surfaces.
Final piston/connecting rod refitting 37 Ensure that the bearing shells are correctly fitted. If new shells are being fitted, ensure that alt traces of the protective grease are cleaned off using paraffin. Wipe dry the shells and connecting rods with a lint-free cloth. 38 Lubricate the cylinder bores, the pistons, and piston rings, then lay out each piston/con-necting rod assembly in its respective position. 39 Start with assembly No 1. Position the piston ring gaps 120° apart, then clamp them in position with a piston nng compressor. 40 Insert Ihe piston/connecting rod assembly into the top of cylinder making sure it is Ihe correct way round. On petrol engines, ensure that the arrow on the piston crown is pointing towards the timing belt end of the engine and on diesel engines, ensure that the cloverleaf-shaped cut-out on the piston crown is towards the front (oil filter side) of the cylinder block. Using a block of wood or hammer handle against the piston crown, tap the assembly into the cylinder until the piston crown is Hush with the top of the cylinder (sea illustrations). 41 Ensure that the bearing shell is still correctly Installed. Liberally lubricate the crankpin and both bearing shells. Taking care not to mark the cylinder bores, pull the piston/connecting rod assembly down the bore and onto the crankpin.
7.40b Inserting the piston/connecting rod assembly into the cylinder bore using a hammer handle (diesel englno) 42 Refit the big-end beanng cap, tightening Its retaining bolts finger-tight at first, Note that Ihe faces with the identification marks must match (which means that the bearing shell locating tabs abut each other). 43 Tighten the bearing cap retaining bolts evenly and progressively to the specified torque setting. On diesel engines tighten the bolts to the Stage 1 torque then angle-tighten them to the specified Stage 2 angle using an angle-measuring gauge, (see illustrations) 44 Once the bearing cap retaining bolts have been correctly tightened, rotate the crankshaft. Check that il turns freely; some stiffness is to be expected if new components have been fitted, but there should be no signs of binding or tight spots. 45 Refit the remaining three piston/ connecting rod assemblies in the same way. 46 Refit the cylinder head, anti-vibration plate (16-valve engines), oil pump pick-up/filter screen assembly and sump with reference to Chapter 2A, 2B or 2C.
8 Crankshaft -removal and inspection 35
Removal 1 Remove the
sump,
oil pump and pick-up tube, and flywheel/driveplate with reference to the relevant Sections of Chapter 2 Parts A, 8 or C. On 16-valve engines, unbolt and remove the anti-vibration plate from the main bearing caps.
7.43a Torque-tightening the big-end bearing cap bolls (diesel engine) 7.43b Angle-tightening the big-end bearing cap bolts (diesel engine)

2D*10 Engine removal and overhaul procedures
8.4 Using a dial gauge to check the crankshaft endfloat 2 Remove the pistons and connecting rods, as described in Section 7. However, If no work fs to be done on the pistons and connecting rods there is no need to remove the cylinder head, or to push the pistons out of the cylinder bores. The pistons should just be pushed far enough up the bores that they are positioned clear of the crankshaft Journals. 3 Unbolt the crankshaft rear oil seal housing from the cylinder block and recover the gasket where fitted. 4 Before removing the crankshaft, check the endfloat using a dial gauge. Push the crankshaft fully one way, and then zero Ihe gauge. Push the crankshaft fully the other way, and check tho endfloat (see Illustration). The result can be compared with the specified amount, and will give an indication as to whether new thrustwashers are required. 6 If a dial gauge is not available, feeler blades can be used. First push the crankshaft fully towards the flywheel end of the engine, then use feeler blades to measure the gap - on petrol engines measure between the centre main bearing thrust washer and the crankshaft web. and on diesel engines measure between the rear main bearing and tha crankshaft web. 6 Note the markings on the main bearing caps which vary according to type. On 8-valve petrol engines there is one line on Ihe cap nearest the timing belt end, two on the second cap, C on the centre cap, then three and four lines on the remaining caps (soo illustration). On 16-valve petrol engines, the caps are marked one to five with a series of lines (one line for the cap nearest the timing
8.6 Main bearing markings (petrol engine)
belt end, two for tho next cap and so on). On diesel engines the caps are marked one to live In the same way but with notches instead ol lines. Note also that on some diesel engines the cap nearest the timing belt end Is not marked and the notches therefore start with No 2 cap. 7 Loosen and remove the main bearing cop retaining bolts, and lift off each bearing cap. Recover the lower bearing shells, and tape them to their respective caps for safe-keeping. On some diesel engines note that the centre main bearing cap botts are longer than the other bolls. 8 Lift the crankshaft Irom the crankcase and remove the upper bearing shells from the crankcase. If the shells are 1o be used again, keep them identified for position. Also remove the thrustwashers from their position either side of the centre main bearing (petrol engines) or rear main bearing (diesel engines) (see illustrations)
Inspection 9 Wash the crankshaft in a suitable solvent and allow It to dry. Flush the oil holes thoroughly, to ensure that ihey are not blocked - use a pipe cleaner or a needle brush il necessary. Remove any sharp edges from the edge of the holes which may damage the new bearings when they are installed. 10 Inspect the main searing and crankpin journals carefully; if uneven wear, cracking, scoring or pitting are evident then the crankshaft should be reground by an engineering workshop, and refitted to the engine with underslze bearings.
11 Use a micrometer to measure the diameter of each main bearing journal. Taking a number of measurements on the surface of each journal will reveal if it Is worn unevenly. Differences in diameter measured at 90" intervals Indicate that the journal is out of round. Differences In diameter measured aiong the length of the journal, indicate that the journal is tapered. Again. If wear is detected, the crankshaft can be reground by an engineering workshop and refitted with undersize bearings. 12 Check the oil seal journals at either end of the crankshaft. If they appear excessively scored or damaged, they may cause the new seals to leak when the engine is reassembled. It may be possible to repair the |ournal; seek the advice of an engmeenng workshop. 13 Measure the crankshaft runoul by setting up a DTI gauge on the centre main bearing journal and rotating the shaft In V - blocks. The maximum deflection of the gauge will indicate Ihe runout. Take precautions to protect the bearing journals and oil seal mating surfaces from damage during this procedure. A maximum runout figure Is not quoted by the manufacturer, but use the figure of 0.05 mm
a»
a rough guido. If the runoul exceeds this figure, crankshaft renewal should be considered • consult your Flat dealer or an engine rebuilding specialist for advico. 14 Refer to Section 10 for details of main and big-end bearing inspection.
9 Cylinder block/crankcase - % cleaning and inspection Sk
Cleaning 1 Remove all external components, brackets and electrical switches/sensors from the block Including the rear engine plate, injection pump/oil filter bracket and gasket, Intermediate shaft bracket, oH vapour breather casing, and coolant pump. Also unboit and remove the ol return tube from the crankcase (see illustrations). For complete cleaning, the core plugs should Ideally be removed. Drill a small hole in the plugs, then insert a self-tapping screw into the hole. Pull out the plugs by
8.8a Removing the thrustwashers.. ... and upper bearing shells (diesel engine) 8.8o Thrustwashers located on the centre main bearing (petrol engine)

2D*10 Engine removal and overhaul procedures
failure, (he cause must be corrected (where applicable) before the engine is reassembled, to prevent it from happening again. 3 When examining the bearing shells, remove them from the cylinder block/crankcase, Ihe main bearing caps, the connecting rods and the connecting rod big-end bearing caps. Lay them out on a clean surface in the same general position as their location in the engine. This will enable you to match any bearing problems with the corresponding crankshaft journal. Do not touch any shell's bearing surface with your fingers while checking it. 4 Din and other foreign matter gets into the engine in a variety of ways. It may be left in the engine during assembly, or It may pass through fillers or the crankcase ventilation system. It may get into the oil, and from there into the bearings. Metal chips from machining operations and normal engine wear are often present. Abrasives are sometimes left In engine components after reconditioning, especially when parts are not thoroughly cleaned using the proper cleaning methods. Whatever the source, these foreign objects often end up embedded In the soft bearing material, and are easily recognised. Large particles will not embed in the bearing, and will score or gouge the bearing and journal. The best prevention for this cause of bearing failure Is to clean all parts thoroughly, and keep everything spotlessly-clean during engine assembly. Frequent and regular engine oil and filter changes are also recommended. 5 Lack of lubrication (or lubrication breakdown) has a number of interrelated causes. Excessive heat (which thins the oil), overloading (which squeezes the oil from the bearing face) and oil leakage (from excessive bearing clearances, worn oil pump or high engine speeds) all contribute to lubrication
breakdown. Blocked oil passages, which can be the result of misaligned oil holes in a bearing shell, will also oil-starve a bearing, and destroy it. When lack of lubrication is the cause of bearing failure, the bearing materiel is wiped or extruded from the steel backing of Ihe bearing. Temperatures may increase to the point where the steel backing turns blue from overheating. 6 Driving habits can have a definite effect on bearing life. Full-throttle, low-speed operation (labouring ihe engine) puts very high loads on bearings, tending to squeeze out the oil film. These loads cause the beanngs to flex, which produces fine cracks in the bearing face (fatigue failure). Eventually, the bearing material will loosen in pieces, and tear away from Ihe steel backing. 7 Short-distance driving leads to corrosion of bearings, because insufficient engine heat is produced to drive off the condensed water and corrosive gases. These products collect in the engine oil, forming acid and sludge. As the oil Is carried to the engine bearings, the acid attacks and corrodes the bearing material. 8 Incorrect bearing installation during engine assembly will lead to bearing failure as well. Tight-fitting bearings leave insufficient bearing running clearance, and will result in oil starvation. Dirt or foreign particles trapped behind a bearing shell result in high spots on the bearing, which lead to failure. 9 Do not touch any shell's bearing surface with your fingers during reassembly: there is a risk of scratching the delicate surface, or of depositing particles of dirt on ft. 10 As mentioned at the beginning of this Section, the bearing shells should be renewed as a matter of course during engine overhaul; to do otherwise is false economy.
Selection 11 Main and big-end bearings are available in standard sizes and a range of undersizes to suit reground crankshafts • refer to the Specifications for details. The engine reconditioner will select the correct bearing shells for a machined crankshaft. 12 The running clearances can be checked when the crankshaft is refitted with its new bearings.
11 Engine overhaul -reassembly sequence
1 Before reassembly begins, ensure that all new parts have been obtained, and that all necessary tools are available. Read through the entire procedure to familiariss yourself with the work Involved, and to ensure that ail items necessary for reassembly of the engine are at hand. In addition to all normal tools and materials, thread-locking compound will be needed. A tube of sealant will also be required for the joint faces that are fitted without gaskets.
2 In order to save time and avoid problems, engine reassembly can be carried out in the following order: a) Crankshaft (Section 12). b) Piston/connecting rod assemblies (Section 7). c) Oil pump (see Part A, B or C - as applicable). d) Sump (see Pan A, BorC-as applicable). e) Flywheel/driveplate (see Part A, B or C • as applicable). 1) Cylinder head (see Part A B or C - as applicable). g) Coolant pump (see Chapter
3)
h) Timing belt tensioner and sprockets, and timing belt (See Part A, B or C- as applicable). I) Engine external components, 3 At this stage, ail engine components should be absolutely clean and dry, with all faults repaired. The components should be laid out on a completely clean work surface.
12 Crankshaft- % refitting and main bearing S running clearance check ^
Crankshaft - initial refitting 1 Crankshaft refitting Is the first stage ol engine reassembly following overhaul. At this point, it is assumed that the crankshaft, cylinder block/crankcase and beanngs have been cleaned, inspected and reconditioned or renewed. 2 Place the cylinder block on a clean, level work surface, with the crankcase facing upwards. Where necessary, unbolt the bearing caps and lay them out in order to ensure correct reassembly. If they are still in place, remove the bearing shells from the caps and the crankcase and wipe out the inner surfaces wilh a clean rag - they musl be kept spotlessly clean. 3 Clean the rear surface of the new bearing shells with a rag and fit ihem on Ihe bearing saddles. Ensure that the orientation lugs on the shells engage with the recesses in the saddles and lhat the oil holes are correctly aligned. Do not hammer or otherwise force the bearing shells into place. It Is critically important that the surfaces of the bearings ore kept free from damage and contamination. 4 Give the newly fitted bearing shells and the crankshaft journals a final clean with a rag. Check that the oil holes In the crankshaft are free from dirt, as any left here will become embedded In the new bearings when Ihe engine is first started. 5 Carefully lay the crankshaft In the crankcase, taking care not to dislodge the bearing shells (see illustration}.
Main bearing running clearance check 8 When Ihe crankshaft and bearings are refitted, a clearance must exist between them

3*2 Cooling, heating and ventilation systems
1 General information and precautions
Genera/ Information The engine cooling/cabin heating system is ol pressurised type, comprising a coolant pump driven by the camshaft timing belt (petrol engine models) or auxiliary drlvebelt (diesel engine models), a crossllow radiator, a coolant expansion tank, an electric cooling fan, a thermostat, heater matrix, and all associated hoses and switches. The system functions as follows: Ihe coolant pump circulates cold water around the cylinder block and head passages, and through the Inlet manifold, heater matrix and throttle body to the thermostat housing. When the engine Is cold, the thermostat remains closed and prevents coolant from circulating through the radiator. When the coolant reaches a predetermined temperature, the thermostat opens, and the coolant passes through the top hose to the radiator. As the coolant circulates through the radiator, it is cooled by the in-rush of air when the car is in forward motion. The airllow is supplemented by the action of the electric cooling fan. when necessary, As the temperature of the coolant in the radiator drops, it flows to the bottom of the radiator by convection, and passes out through the bottom hose to the coolant pump - the cycle is then repeatod, When the engine is at normal operating temperature, the coolant expands, and some of It is displaced into the expansion tank. Coolant collects In the tank, and ts returned to Ihe radiator when the system cools. On petrol engine models, the expansion tank is integrated into the side of the radiator. On diesel engine models, and certain petrol engine models with air conditioning, the tank is a separate unit, mounted on the right hand side of the engine compartment. On turbo diesel engine models, the coolant is also passed through a supplementary engine oil cooler, to assist In controlling the engine lubricant temperature. Tho electric cooling fan mounted in front of the radiator is controlled by a thermostatic switch. At a predetermined coolant temperature, the swilch/sensor actuates the tan lo provide additional airflow through the radiator, The switch cuts the electrical supply to the Ion when the coolant temperature has dropped below a preset threshold (see Specifications).
Precautions

A


Warning: Do not attempt to remove the expansion tank pressure cap, or to disturb any part of the cooling system, whlio the engine is hot, as then is a high risk of scalding, tf the expansion tank pressure cap must be removed before the
engine and radiator have fulty cooled (even though this is not recommended?, the pressure in the cooling system must first be relieved. Cover the cap with a thick layer of cloth, to avoid scalding, and slowly unscrew the pressuro cap until a hissing sound Is heard. When the hissing stops, indicating that the pressure has reduced, slowly unscrew the pressure cap until it can be removed; If more hissing sounds are heard, wait until they have stopped before unscrewing the cap completely. At all times, keep your face well away from the pressure cap opening, and protect your hands.

A


Warning: Do not allow antifreeze to come into 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 in an open container, or In a puddle In the driveway or on the garage floor. Children and pets are attracted by its sweet smell, but antifreeze can be fatal tf ingested.

A


Warning: If the engine is hot, the electric cooling fan may start rotating even if the engine and ignition are switched off. Be careful to keep your hands, hair, and any loose clothing well clear when working In the engine compartment.
2 Cooling system hoses - f&> disconnection and renewal ^
1 The number, routing and pattern of hoses will vary according to model, but the same basic procedure applies. Before commencing work, make sure that the new hoses are to hand, along wilh new hose clips if needed, it is good practice to renew the hose clips at the same time as the hoses. 2 Drain the cooling system, as described in Chapter 1A or 18, saving the coolant if it is fit for re-use. Apply a little penetrating oil onto the hose clips if they are corroded. 3 Release the hose clips from the hose concerned. Three types of clip are used; worm-drive. spring and 'sardine-can'. The worm-drive clip is released by turning its screw anti-clockwise. The spring clip Is released by squeezing Its tags together with pliers, at the same time working the cbp away from the hose stub. The sardine-can clips are not re-usable, and are best cut off with snips or side cutters. 4 Unclip any wires, cables or other hoses which may be attached to the hose being removed. Make notes for reference when reassembling If necessary. 5 Release the hose from its stubs with a twisting motion. Be careful not to damage the stubs on deltcate components such as the radiator, or thermostat housings. If the hose Is stuck fast, the best course is often to cut it off using a sharp knife, but again be careful not to damage the stubs.
6 Before fitting the new hose, smear the stubs with washing-up liquid or a suitable rubber lubricant to aid fitting. Do not use oil or grease, which may attack the rubber. 7 Fit the hose clips over the ends of the hose, then fit the hose over its stubs. Work the hose Into position. When satisfied, locate and tighten the hose dips. 6 Refill the cooling system as described In Chapter 1A or 1B. Run the engine, and chock that there are no leaks. 9 Recheck the tightness of Ihe hose clips on any new hoses after a few hundred miles. 10 Top-up the coolant level if necessary.
3 Radiator -
removal,
inspection and refitting
Removal Note: If leakage is the reason for removing
the
radiator, bear In mind that minor leaks can often be cured using proprietary radiator sealing compound, with the radiator in situ. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). On diesel engine models, unbolt the relay bracket from the side of the battery tray. 2 Drain the cooling system as described In Chapter 1A or 1B. 3 On 1242 cc (16-valve) petrol engine models, remove the air cleaner and Inlet ducts as desenbed In Chapter 4B, 4 Slacken the clips and disconnect Ihe (op and bottom coolant hoses from the radiator. In addition on diesel engine models, and petrol engine models with a remotely-sited expansion tank, disconnect the expansion tank coolant hose from the right hand side ol the radiator (see Illustrations), 5 Unscrew the fixings and lift the plastic trim panel from above the front bumper Unscrew the bolt(s) securing tho radiator to the upper body panel (see Illustration). Note that the radiator and cooling fan assembly share the same upper mounting bolt. 6 Unbolt the cooling fan(e) and shroud assembly from Ihe rear ot the radiator, as described in Section 5.
3.4a Slacken the clip and disconnect the radiator bottom hose