2D*10 Engine removal and overhaul procedures
Valves and associated components 35 Examine the head of each vaive for pitting, burning, cracks, and general wear. Check the valve stem for scoring and wear ridges. Rotate the valve, and check lor any obvious indication that it Is bent. Look tor pits or excessive wear on the tip of each valve stem. Renew any valve that shows any such signs of wear or damage. 36 if the valve appears satisfactory at this stage, measure the vaive stem diameter at several points using a micrometer. Any significant difference in the readings obtained Indicates wear of the valve stem. Should any of these conditions be apparent, the valve(s) must be renewed. 37 If the valves are In satisfactory condition, they should be ground (lapped) into their respective seats, to ensure a smooth, gas-tight seal. If the seat is only tightly pitted, or if it has been re-cut, fine grinding compound only should be used to produce the required finish. Coarse valve-grinding compound should nor be used, unless a seat is badly bumed or deeply pitted, If this is the case, the cylinder head and valves should be Inspected by an expert, to decldo whether seat re-cutting, or even the renewal of the valve or seat insert (where possible) is required. 38 Valve grinding Is carried out as follows. Place the cylinder head upside-down on blocks on a bench. 39 Smear a trace of (the appropriate grade of) valve-gnndtng compound on the seat face, and press a suction grinding tool onto the valve head. With a semi-rotary action, grind
6.48 Compressing the vaive spring and fitting the split collets
them
the valve head to its seat, lifting the valve occasionally to redistribute tho grinding compound (see Illustration). A light spring placed under the valve head will greatly ease this operation 40 If coarse grinding compound Is being used, v/ork only until a dull, matt even surface Is produced on both the valve seal and the valve, then wipe off tho used compound, and repeat the process with fine compound. When a smooth unbroken ring ol light grey malt finish Is produced on both the valve and seat, the grinding operation is complete. Do not grind-In the valves any further than absolutely necessary, or the seat will be prematurely sunk into the cylinder head. 41 When all the valves have been ground-m, carefully wash off all traces of grinding compound using paraffin or a suitable solvent, before reassembling the cylinder head. 42 Examine the valve springs for signs of damage ano discoloration, If possible compare the length of the springs with new ones and renew them if necessary. 43 Stand each spring on a flat surface, and check ft tor squareness. If any of the springs are damaged, distorted or have lost mar tension, obtain a complete new set of springs. It Is normal to renew the valve springs as a matter of course if a major overhaul is being earned out. 44 Renew (he valve stem oil seals regardless of their apparent condition.
Reassembly 45 Lubricate the stems of the valves, and insert the valves into their original locations
6.53 Tightening the camshaft bearing cap nuts (diesel engines)
6.46 Using a socket to press the valve stem seals onto the guides
(see illustration). If new valves are being fitted, insert them Into the locations to which they have been ground. 46 Refit the spring sea( then, working on the first valve, dip the new valve stem sesl in fresh engine oil. Carefully locate it over the valve and onto the guide. Take care not to damage the seal as it Is passed over the valve stem. Use a suitable socket or metal tube to press the seal firmly onto the guide (sea Illustration). 47 Locate the valve spring on top of its seat, then refit the spring retainer. 48 Compress the valve spring, and locate the split collets in the recess in the valve stem. Release the compressor, then repeat the procedure on the remaining valves (see illustration)
Use a dab o) grease to hold Uiejitts* the collets In position on the HlNT valve stem while the spring compressor is released.
49 With ail the valves Installed, place the cylinder head on blocks on the bench and, using a hammer and Interposed block ol wood, top the end of each valve stem to settle the components. 50 On diesel engines, refit the swirl chambers together with their washers and tighten the retaining collars to the specified torque. 51 Oil the cam followers and locate them In their correct positions in the cylinder head. Locate the shims In the cam followers making sure they are in their original positions. 52 Oil the journals then locate the camshaft m the cylinder head with the cam lobes of No 1 cylinder facing upwards (ie No 1 cylinder at TDC). 53 Refit the bearing caps In their correct positions and progressively tighten the nuts/bolts to the specified torque (sea illustration). On petrol engines locate the lubrication pipe on Ihe head and press in the oil feed stub before refitting the bolts. 54 On diesel engines fit a new oil sea) to the right-hand side mount, then refit both side mounts together with new gaskets, Tighten the right-hand mount bolts. Also refit the coolant cover and thermostat housing together with new gaskets (see illustrations).
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)
Fuel system - diesel models
4C*3
7.4 Unscrew the access screw from the 7.5 Dial gauge and adapter (Bosch) rear of the Injection pump (Bosch)
7 Injection timing ^ (Bosch fuel injection pump) -checking and adjustment ^
Caution: Some of the Injection pump uttlngs and access plugs may be sealed ty the manufacturers at the factory, using
paint
or locking wire and lead seals. Do not
disturb
the seals If the vehicle is still within the warranty period, otherwise the warranty will be invalidated. Also do not attempt the timing procedure unless
accurate
Instrumentation Is available. Note: To check the injection pump timing a special
timing
probe and mounting bracket is required. Without access to this piece of
tquipment.
injection pump timing should be intrusted to a Fiat dealer or other suitably
eqwpped
specialist. 1
H
the Injection timing is being checked with ffie pump in position on the engine, rather rian as part ot the pump refitting procedure, disconnect the battery negative terminal (refer to
Disconnecting
the battery in the Reference S«ction of this manual), and remove the air rtel ducting from the front of the engine. 2 Unscrew the union nuts and disconnect the injector pipes from the Injection pump and injectors. Counterhold the unions on the pump, while unscrewing the pipe-to-pump irion
nuts.
Remove the pipes as a set. Cover open unions to keep dirt out, using small plastic bags, or fingers cut from discarded
ibut clean!)
rubber gloves. 3 Referring to Chapter 2C, set the engine at
TDC on
cylinder No 1. 4 Unscrew the access screw, situated In the centre of the four injector pipe unions, from the rear of the Injection pump (see illustration). As the screw Is removed, position a suitable container beneath the
pump
to catch any escaping fuel, Mop up any tpilt fuel with a clean cloth. 5 Screw the adapter into the rear of the pump
and
mount the dial gauge in ihe adapter (see •ustration). If access to the special Fiat *Japter cannot be gained, they can be purchased from most good motor factors. Position the dial gauge so that its plunger is at
Ifce
mid-point of its travel and securely tighten Ite adapter locknut. 6 Slowly rotate the crankshaft first back then towards whilst observing the dial gauge, to ctotermlne when the Injection pump piston is
a',
the bottom of Its travel (BDC), When the pston Is correctly positioned, zero the dial
7 Rotate the crankshaft slowly in the correct direction until the TDC timing marks are tfjned on both the crankshaft, camshaft and rjecbon pump sprockets.
6
The reading obtained on the dial gauge should be equal to the specified pump timing measurement given in the Specifications at ew start of this Chapter, If adjustment is necessary, slacken the fronl and rear pump mounting nuts/bolts and slowly rotate the
pump body until the point is found where the specified reading Is obtained. When the pump is correctly posilioned, tighten both its front and rear mounting nuts and bolts securely. 9 Rotate the crankshaft through one and three quarter rotations in the normal direction of rotation. Find the injection pump piston BDC as described in paragraph 6 and zero the dial gauge. 10 Rotate the crankshaft slowly in the correct direction of rotation until the TDC marks are aligned. Recheck the timing measurement. 11 If adjustment is necessary, slacken the pump mounting nuts and bolts and repeat the operations In paragraphs 8 to 10. 12 When the pump timing Is correctly set, unscrew the adapter and remove the dial gauge. 13 Refit the screw and sealing washer to the pump and tighten it securely. 14 If the procedure is being carried out as part of the pump refitting sequence, proceed as described in Section 5, 15 If the procedure is being carried out with the pump fitted to the engine, refit the injector pipes tightening their union nuts to the specified torque setting. Reconnect the battery and refit the air inlet ducting. 16 Start the engine, and check for any leakage at the luel unions. To enable the engine to start it may be necessary to loosen the injector union nuts while turning tho engine on the starter motor in order to purge trapped air. 17 Check and if necessary adjust the idle speed as described in Chapter 1B.
8.4 Removing the injection pump timing inspection plug (Lucas)
8 injection timing ^ (Lucas fuel injection pump) - ^ checking
and
adjustment ^
Caution: Some of the injection pump settings and access plugs may be sealed by the manufacturers at the factory, using paint or locking wire and lead seo/s. Do not disturb the seals if the vehicle Is still within the warranty period, otherwise tho warranty will be Invalidated. Also do not affempf the timing procedure unless accurate instrumentation is available.
Note: To check the Injection pump timing a speciai timing probe and mounting bracket Is required. Without access to this piece of equipment, injection pump timing should be entrusted to a Fiat dealer or other suitably equipped specialist. 1 If the injection timing is being checked with the pump tn position on the engine, rather than as part of the pump refitting procedure, disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual), and remove the air inlet ducting from the front of the engine. 2 Unscrew the union nuts and disconnect the injector pipes from the Injection pump and In-jectors. Counterhold the unions on the pump, while unscrewing the pipe-to-pump union nuts. Remove the pipes as a set. Cover open unions to keep dirt out. using smalt plastic bags, or fingers cut from discarded (but clean!) rubber gloves. 3 Referring to Chapter 2C, set the engine at TDC on cylinder No 1, then turn the crank-shaft backwards (anti-clockwise) approx-imately a quarter of a turn. 4 Unscrew the access plug from the guide on the top of the pump body and recover the sealing washer (soe Illustration). Insert the special liming probe Into the guide, making sure it Ib correctly seated against the guide seating washer surface. Note: The timing probe must be seated against the guide sealing washer surface and not the upper lip of the guide for the measurement to be accurate. 5 Mount the bracket on the pump guide (using adapter tool) and securely mount the dial gauge {dial test indicator) In the bracket
expert22 fl/i* http://rutracker.org
Fuel system - diesel models 4C*3
8.5 Dial gauge (1), mounting bracket (2) and setting rod (3) In position on the injection pump (Lucas)
so that Its tip Is In contact with the bracket linkage (see Illustration). Position the dial gauge so that its plunger is at the mid-point of its travel and zero the gauge. 6 Rotate the crankshaft slowly in the correct direction of rotation (clockwise) until the crankshaft is positioned at TDC on No 1 piston with ell the sprocket timing marks aligned. 7 Check the reading on the dial gauge which should correspond to the value marked on the pump (there is a tolerance of * 0.04 mm). The timing value may be marked on a plastic disc attached to the front of the pump, or alternatively on a tag attached to Ihe pump control lever (see illustrations). 8 If adjustment is necessary, slacken the front pump mounting nuts/bolt and the raar mounting bolt, then slowly rotate tne pump body until the point is found where the specified reading is obtained on the dial gauge (access to the lower front bolt is gained through the hole in the injection pump sprocket). When the pump Is correctly positioned, tighten both its front mounting nuta/bolt and the rear bolt to their specified torque settings. 9 Withdraw the timing probe slightly, so that it
positioned clear of the pump rotor dowel. Rotato the crankshaft ihrough one and three quarter rotations in the normal direction of rotation. 10 Slide the timing probe back Into position ensuring that it Is correctly seated against the guide sealing washer surface, not (he upper Hp, then zero the dial gauge. 11 Rotate the crankshaft slowly in the correct direction ol rotation to the TDC position and recheck the timing measurement 12 If adjustment Is necessary, slacken the pump mounting nuts and bolt and repeat the operations in paragraphs 6 to 11. 13 When the pump timing is correctly set. remove the dial gauge and mounting bracket and withdraw the timing probe. 14 Refit the screw and sealing washer to the guide and tighten it securely.
8.7a Pump timing value (x) marked on plastic diso (Lucas)
15 If the procedure is being carried out as part of the pump refilling sequence, proceed as described in Section 5. 16 If the procedure is being carried out with the pump fitted to the engine, refit the injector pipes tightening their union nuts to the specified torque setting. Reconnect the battery and refit the air inlet ducting. 17 Start the engine, and check for any leakage at the fuel unions. To enable the engine to start it may be necessary to loosen tho injector union nuts while turning the engine on the starter motor in order to purge trapped air. 18 Check and If necessary adjust the Idle speed as described In Chapter 1B.
9 Fuel Injectors -testing, removal and refitting Sk ^
A
Warning: Exercise extreme caution when working on the fuel injectors. Never expose the hands or any part of the body to Injector spray, as the high working pressure can cause the fuel to pen ot rate the skin, with possibly fatal results. You are strongly advised to have any work which involves testing the injectors under pressure carried out by a dealer or fuel Injection specie list.
Testing 1 Injectors do deteriorate with prolonged uso, and it is reasonable to expect them to need reconditioning or renewal after 60 000 miles
8.7b Pump timing values marked on label (1) and tag (2) (Lucas)
(100 000 km) or so. Accurate testing, overhaul and calibration of the Injectors must be left to a specialist. A defective injector which Is causing knocking or smoking can be located without dismantling as follows. 2 Run the engine at a fast idle. Slacken each Injector union In turn, placing rag around the union to catch spilt fuel, and being careful not to exposa the skin to any spray. When tho union on the defective Injector is slackened, the knocking or smoking will stop.
Removal 3 Remove ihe air Inlet ducting from tho front part of the onglne. 4 Carefully clean around the Injectors and injector pipe union nuts. 5 Pull the leak-off pipes from the injectors (see illustration). 6 Unscrow the union nuts securing Ihe injector pipes to the fuel Injection pump. Counterhold the unions on the pump when unscrewing the nuts. Cover open unions lo keep dirt out, using small plastic bags, or fingers cut from discarded (but clean!) rubber gloves. 7 Unscrew the union nuts and disconnect the pipes from the ln|ectors, If necessary, the Injector pipes may be completely removed-Note carefully the locations of the pipe clamps, for use when refitting. Cover tho onds ot (he injectors, to prevent dirt ingress. 8 Unscrew the injectors using a deep socket or box spanner, and remove Ihem from the cylinder head (see Illustration). 9 Recover the tire seal washers from the cy-linder head and discard them (see illustration).
9.5 Disconnecting the Injector leak-off pipes 9.8 Removing an injector
Fuel system - diesel models
4C*3
9.9 Removing the fire seal washor 9.13 Tightening an injector with a torque wrench
Refitting 10 Obtain new fire seal washers. 11 Take care not to drop the Injectors, or tfow the needles at their tips to become damaged. The injectors are prectsion-mado to Ine knits, and must not be handled roughly. In particular, never mount them in a bench vice. 12 Commence refitting by inserting the fire
seal
washers {convex face uppermost}. 13 Insert the injectors and tighten them to the specified torque (see illustration). 14 Refit the injector pipes and tighten the union nuts. Make sure the pipe clamps are in Iteir previously-noted positions. If the clamps
are
wrongly positioned or missing, problems may be expenenced with pipes breaking or splitting,
15 Reconnect the leak-off pipes. 16 Refit the air ducting. 17 Start the engine, and check for any leakage at the fuel unions. To enable the engine to start it may be necessary to loosen the Injector union nuts while turning the engine on the starter motor in order to purge trapped air.
10 Fuel gauge sender unit -removal and refitting
Refer to Chapter 4A, hov/ever note that the unit does not Incorporate a pump (see illustrations).
11 Fuel tank -removal and refitting
Refer to Chapter 4A, however note that in addition a safety valve with an anti-roll device is fitted in the top of the tank with a ventilation pipe to the front of the tank. The fuel gauge sender unit does not Incorporate a pump as this unit is located In the injection pump.
12 Inlet manifold - ^ removal and refitting %
Note: The Inlet and exhaust manifolds are both located on the rear of the engine and share the same securing bolts and gasket. Although the following procedure describes removal of the Inlet manifold separately it may be necessary to remove the exhaust manifold as well In order to renew the gasket.
Removal 1 Remove the air cleaner and ducting as described in Section 2. 2 Unbolt and remove the relay guard and bracket from the left-hand side of the engine. 3 On turbo models disconnect the air duct from the inlet manifold elbow. If necessary the elbow can be unbolted from the manifold and the sealing ring removed. 4 Unscrew the nuts securing the inlet manifold to the cylinder head noting the position of the support bracket. Note lhat some of the nuts also secure the exhaust manifold. Withdraw the inlet manifold from the studs (see illustrations), 5 Examine the gasket. If It is damaged it will be necessary to remove the exhaust manifold in order to renew it.
Refitting 6 Refitting Is a reversal of removal, but tighten all nuts and bolts lo the specified torque.
12.4c Removing the Inlet manifold
4D*2 Exhaust and emission control systems
2.2 Charcoal canister location behind tho right-hand headlight
conditions, via a plunger valve, The system is controlled electronically by means of an emissions system control unit. Evaporative emission control • petrol models To minimise the escape of unburned hydrocarbons Into the atmosphere, an evaporallve loss emission control system is fitted to petrol models, The fuel tank filler cap Is sealed and a charcoal canister is mounted underneath the right-hand headlamp to collect the petrol vapours released from the fuel contained In the fuel tank. It stores them until they can be drawn from the canister (under the control of the fuel Injection/ignition system ECU) via the purge valve into the Inlet tract, where they are then burned by the engine during normal combustion. To ensure thai the engine runs correctly when it is cold and/or idling and to protect the catalytic converter from the effects of an over-rich mixture, the purge control valve is not opened by the ECU until the engine has warmed up, and the engine is under load; the valve solenoid is then modulated on and off to allow the stored vapour to pass into the inlet tract.
Exhaust systems The exhaust system comprises the exhaust manifold, an exhaust downpipe, • catalytic convorter, an intermediate pipe with silencer, and a tailpipe with silencer, On turbo diesel models the turbocharger is fitted between ihe exhaust manifold and the downpipe.
5.5a On 16-valve engines, undo the bolts and remove the manifold heat shield...
2 Evaporative loss emission ^ control system - information and component renewal ^
Information 1 The evaporative loss omission control system consists of the control solenoid (or purge valve), the activated charcoal filter canister and a series of connecting vacuum hoses. 2 The control solenoid and charcoal canister are both mounted on the right-hand side of the engine compartment behind the headlight (see illustration).
Component renewal
Control solenoid 3 With the bonnet open, disconnect the hoses from the control solenoid on the top of the charcoal canister. 4 Disconnect the wiring and remove the solenoid. 5 Refitting is a reversal of removal. Charcoal canister 6 Remove Ihe control solenoid as desenbed previously. 7 Disconnect Ihe fuel tonk hose from the canister 8 Detach the mounting and remove the canister. 9 Refitting Is a reversal of removal. Multifunction valve 10 The multifunction valve >s mounted on top of the luel tank. Removal and refitting is similar to that described for the tank sender gauge/pump (refer to Chapter 4A or 4B).
3 Crankcase emission system - general information
The crankcase emission control system consists of a hose from the camshaft cover to the air cloanor with a branch to Ihe throttle body. The main hose Incorporates a flame trap and the Inlet to the throttle body incorporates a calibrated hole.
5.5b ... then remove the bracket
The system requires no attention other than to check at regular intervals that tho hoses are free of blockages and undamaged.
4 Lambda oxygen sensor -removal and refitting &
Note: 7?5e Lambda oxygen sensor is doiicata and will not work if it is dropped or knocked, it its power supply is disrupted, or if any cleaning materials are used on it.
Removal 1 The sensor Is threaded Into the exhaust front downpipe. Access if best gained Irom underneath the vehicle. Apply the handbrake then )ack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). 2 Disconnect the sensor wiring connector located on the front of the engine. 3 Working beneath the vehicle, unscrew the sensor, taking care to avoid damaging the sensor probe as it Is removed- Note: As a flying lead remains connected to the sensor after it has been disconnected, if the correct spanner is not available, a slotted socket
will
be required to remove the sensor.
Refitting A Apply a little anti-selze grease to (he sensor threads • avoid contaminating the probe tip. 5 Refit the sensor to the downpipe. tightening it to the correct torque. Reconnect the wiring. 6 Lower the vohicle to the ground.
5 Exhaust manifold - % removal and refitting jk
Petrol models
Removal 1 On 1242 cc (16-valve) engines, remove tho air cleaner and inlet system components as described in Chapter 48. 2 Firmly apply the handbrake, then jock up the front of the car and support It securely on axle stands (see Jacking and vehicle support). 3 Disconnect the oxygen sensor wiring or alternatively romovo Ihe sensor completely. 4 Unscrew the nuts and disconnect the exhaust downpipo from Ihe exhaust manifold flange. Recover the gasket. 5 On 1242 cc (16-valve) engines, undo the bolts and remove the manifold heat shield, then remove the bracket at the timing belt end of the manifold (seo Illustrations). 6 Unscrew the mounting nuts, remove the washers, and recover any additional brackets fitted over the studs, noting their locations. Withdraw the manifold from the studs on the cylinder head. 7 Recover the gaskets from Ihe studs.
4D*3 Exhaust and emission control systems
Refitting 8 Refitting is a reversal of the removal pro-cedure but fit new gaskets. Tighten the nuts lo the specified torque.
Diesel models Note: On diesel models the inlet and exhaust
manifolds
are located on the rear of the engine
end
share the same securing nuts and gasket. Removal 8 Remove the inlet manifold as described In Part
C
of this Chapter. 10 Firmly apply the handbrake, then jack up lite front of tho car and support it securely on axle stands (see Jacking and vehicle support). 11 Straighten the tab washers (where fitted), then unscrew and remove the exhaust downpipe retaining nuts. Detach the downpipe from the manifold/turbocharger. Suitably support the downpipe. 12 Undo the manifold-to-cylinder head securing nuts and withdraw the manifold (see Illustration). 13 Separate the turbocharger from the manifold with reference to Chapter 4C. 14 Remove the gasket and clean the mating
(aces
of the manifold, cylinder head and down-pipe flange (see illustration). The gasket must
be
renewed when refitting the manifold, Refitting
15 Refitting is a reversal of the removal procedure but fit a new gasket. Tighten the retaining nuts to the specified torque and where necessary lock them by bending over
the
tocktabs.
6 Exhaust system - % general information and ^ component renewal
Genera/ Information 1 A three section exhaust system is fitted consisting of a twin-branch front downpipe, a catalytic converter, and a tailpipe with two silencers. The downpipe-to-manifold and downpipe-to-catalytic converter joints are both of flange and gasket type, whereas the remaining joint Is of the sleeve type secured
witn
a clamp ring (see illustration). 2 The system is suspended throughout its entire length by rubber mountings.
Removal 3 Each exhaust section can be removed individually or, alternatively, the complete system can be removed as a unit. Where separation of the rear sleeve Joint is necessary, it may be more practical to remove
the
entire system rather than try and separate
the Joint
In position. 4 To remove the system or part of the system, first jack up the front of the vehicle and support on axle stands (see Jacking and nhlcle support), Alternatively position the
vehicle
over an inspection pit or on car ramps.
5.12 Removing the exhaust manifold (diesel engine) Downpipe 5 Support the catalytic converter using an axle stand or blocks of wood. Where applicable on petrol models, refer to Section 4 and remove the oxygen sensor from the exhaust downpipe. 6 Unscrew and remove the bolts securing the downpipe to tha catalytic converter, then separate the joint and recover the gasket. 7 Bend back the locktabs (where fitted) then unscrew the nuts securing the downpipe to the exhaust manifold/turbocharger. and lower the downpipe, Recover the gasket. Catalytic converter
8 Support the tailpipe section of the exhaust using an axle stand or blocks of wood. 9 Unscrew and remove the bolts securing the downpipe to the catalytic converter, then separate the joint and recover the gasket. 10 Unscrew the clamp bolt and separate the converter from the tailpipe section. 11 Release the mounting rubber and remove the converter from under the vehicle. Tailpipe and silencers 12 Support the catalytic converter using an axle stand or blocks of wood. 13 Unscrew the clamp bolt and separate the catalytic converter from the tailpipe section. 14 Release the tailpipe section from its mounting rubbers and remove from under the vehicle. Complete system 15 Disconnect the downpipe from the ex-haust manifold as described in paragraph 7.
6.1 Exhaust clamp ring securing the tailpipe to the front exhaust system
5.14 Removing the oxhaust manifold gasket (diesel engine) 16 With the aid of an assistant, free the system from all its mounting rubbers and manoeuvre it out from underneath the vehicle. Heatshield 17 The heatshield is secured to the underbody by bolts and Is easily removed once the exhaust system has been removed.
Refitting 18 Each section is refitted by a reverse of the removal sequence, noting the following points. a) Ensure that all traces of corrosion have been removed from the flanges and renew ail necessary gaskets. b) Inspect the rubber mountings for signs of damage or deterioru tion and renew
as
necessary. c) Before refitting the tailpipe joint, smear some exhaust system jointing paste to the joint mating surfaces to ensure an air-tight seal. Tighten the clamp bolt. d) Prior to fully tightening the rear joint damp, ensure that all rubber mountings are correctly /ocafed and that there is adequate clearance between the exhaust system and vehicle underbody.
7 Catalytic converter -general information and precautions
The catalytic converter is a reliable and simple device which needs no maintenance In itself, but there are some facts of which an owner should be aware if the converter is to function properly for its full service life.
Petrol models a) DO NOT use leaded petrot In a car equipped with a catalytic converter - Ihe lead will coat the precious metals, redudng their converting efficiency
and
will eventually destroy the converter. b) Always keep the ignition and fuel systems well-maintained in accordance with the manufacturer's schedule. c) If the engine develops a misfire, do not drive the car at all (or at least as little
as
possible) until the fault is cured.
Braking system 9®5
2 Rotate the brake disc by hand and examine the whole of the surface area swept by the brake pads, on both sides ot the disc. Note: /( will bo necessary to remove the front brake pads to allow an adequate inspection of the disc's rear surface; refer to Section 2 tor details. 3 Typically, the disc surface will have a polished appearance and should be free from heavy scoring. Smooth rippling is produced by normal operation and does not indicate excessive wear. Deep scoring and cracks, however, are indications of more serious damage in need of correction. 4 If deep scoring Is discovered, it may be possible to have the disc reground to restore the surface, depending on the extent of the damage. To determine whether this is a feasible course of action, it will be necessary to measure the thickness of the disc, as described later. 5 Check the whole surface of the disc for cracks, particularly around the roadwheel bolt holes. A cracked disc mutt be renewed. 6 A ridge of rust and brake dust at the inner and outer edges of the disc, beyond the pad contact area is normal - this can be scraped tway quite easily. 7 Raised ridges caused by the brake pads eroding the disc material, however, are an indication of excessive wear. If close examination reveals such ridges, the oiicknoss of the disc must be measured, to usess whether it is still fit for use. 8 To measure the thickness of the disc, take readings at several points on the surface using a micrometer. In the area swept by the brake pads (see Illustration). Include any points where the disc has been scored: align me Jaws of the micrometer with the deepest ares of scoring, to get a true indication of the extent of the wear. Compare these ineasurements with the limits listed in the Specifications. If the disc has worn below its minimum thickness, at any point, it must be renewed. 9 If the discs are suspected of causing brake luddor, check the disc runout, using one of
me
following methods: Runout measurement -
DTI
gauge method 10 Refit the four roadwheel bolts, together
w.1h
one M14 plain washer per stud • this will ensure adequate disc to hub contact. Tighten te studs to 5 Nm (4 Ibf ft). 11 Clamp the DTI gauge to a stand and attach the stand, preferably via a magnetic oase. to the strut mounting bracket. Align the jauge so that its pointer rests upon the area of the dtsc swept by the brake pads, on an arc i mm from the outer edge of tho disc (soe illustration). 12 Zero the gauge and slowly rotate the disc trough one revolution, observing tho pointer rcovement. Note the maximum deflection recorded and compare the figure with that >«ted In Specifications.
4.8 Measuring brake disc thickness with a micrometer
Runout measurement -feeler blade method 13 Use the feeler blades to measure the clearance between the disc and a convenient fixed point, such as the disc backplate. Rotate the disc and measure the variation in clearance at several points around the disc, Compare the maximum figure with that listed in Specifications. 14 If the disc runout Is outside of its specified tolerance, first check that the hub Is not worn (see Steering and suspension check in Chapter 1A or 1B). If the hub is In good condition, remove the disc (as described later in this Section), rotate it through 180° and refit it. This may improve the seating and eradicate Ihe excessive runout. 15 If the runout is still unacceptable, then It may be possible to restore the disc by regrinding; consult your Fiat dealer or a machine shop for a professional opinion - it may prove more economical to purchase a new disc. If the disc cannot be reground, then it must be renewed.
Removal 16 Mark the relationship between the disc and the hub with chalk or a marker pen, to allow correct refitting. 17 To allow the disc to be removed, undo the two bolts securing (he brake caliper mounting bracket to the hub carrier (see illustration 3.7). Withdraw the brake caliper and mounting bracket assembly, complete with brake pads, from the hub carrier, and hang it from a rigid point on the suspension, using v/lre or a
4.18a Slacken and remove the disc locating studs ...
4.11 Brake disc runout measurement - DTI gauge method
cable-tie. Oo not allow it to dangle freely as this will strain the brake hose. 18 Slacken and remove the disc locating stud(s). Support the disc as you do this and lift it off as it becomes free (see illustrations). 19 Remove the polished glaze from the surface of the disc with sand/emery paper. Use small, circular motions to avoid producing a directional finish on the surface.
Refitting 20 If a new disc Is being fitted, remove the protective coating from the surface U9ing an appropriate solvent. 21 Locate Ihe disc on ihe hub so that the roadwheel bolt and locating stud holes are all correctly lined up; use the alignment marks made during removal. If the disc is being removed in an attempt to improve seating and hence runout, turn the disc through 180° and then refit it. 22 Refit the locating stud and retaining screw, tightening them securely. 23 Re-check the disc runout, using one of the methods described earlier in this Section. 24 Refil the brake caliper and mounting bracket assembly to the hub carrier. Coat the threads of the mounting bolts with locking compound, then tighten them to the specified torque. 25 Depress the brake pedal several times to bnng the brake pads into contact with the disc. 26 Refit the roadwheel and lower the vehicle to the ground. Tighten the roadwheel bolts to the specified torque. 27 Check the hydraulic fluid level as described in Weekly checks.
4,18b ... and lift off the disc as It becomes free