Peugeot 405 Manual

Cylinder head - removal and refitting
XU petrol engine in-car repair procedures / Cylinder head - removal and refitting


Removal
1 Remove the battery and its mounting tray with reference to Chapter 5A.

2 Drain the cooling system as described in Chapter 1.

3 Align the engine assembly/valve timing holes as described in Section 3, locking both the camshaft sprocket and crankshaft pulley in position, and proceed as described under the relevant sub-heading. Do not attempt to rotate the engine whilst the pins are in position.

8-valve engines
4 Remove the cylinder head cover as described in Section 4, and remove the air cleaner mounting bracket from the rear of cylinder head.

5 Note that the following text assumes that the cylinder head will be removed with both inlet and exhaust manifolds attached; this is easier, but makes it a bulky and heavy assembly to handle. If it is wished first to remove the manifolds, proceed as described in Chapter 4.

6 Working as described in Chapter 4, disconnect the exhaust system front pipe from the manifold. Where necessary, disconnect or release the lambda sensor wiring, so that it is not strained by the weight of the exhaust.

7 Disconnect the following according to model, as described in Chapter 4: a) On fuel injection models, depressurise the fuel system, and disconnect the fuel feed and return hoses. Plug all openings, to prevent loss of fuel and the entry of dirt into the system.

b) On carburettor models remove the carburettor and disconnect the fuel hoses from the fuel pump.

c) Disconnect the accelerator cable.

d) Disconnect the vacuum servo unit vacuum hose, coolant hose and all the other relevant vacuum/breather hoses, from the inlet manifold and on fuel injection models the throttle body/housing.

e) Undo the retaining nut, and position the oil filler neck clear of the inlet manifold.

f) On fuel injection models, disconnect the three electrical connector plugs from the throttle body.

g) On fuel injection models, disconnect the wiring connectors from the throttle potentiometer and the fuel injectors, and free the wiring loom from the manifold.

h) Where necessary, remove the idle speed auxiliary air valve.

8 Slacken the retaining clips, and disconnect the coolant hoses from the thermostat housing (on the left-hand end of the cylinder head).

9 Depress the retaining clip(s), and disconnect the wiring connector(s) from the electrical switch(es) and/or sensor(s) which are screwed into the thermostat housing, or into the left-hand end of the cylinder head (as appropriate).

10 Refer to Section 8 and disconnect the timing belt from the camshaft sprocket; if preferred, completely remove the timing belt.

11 Jack up the front of the car and support on axle stands (see Jacking and Vehicle Support).

12 Unscrew and remove the horizontal bolt from the engine rear mounting link beneath the rear of the engine.

13 Place a jack beneath the engine, with a block of wood on the jack head. Raise the jack until it is supporting the weight of the engine.

14 Slacken and remove the three nuts securing the engine/transmission right-hand mounting bracket to the engine bracket.

Remove the single nut securing the bracket to the mounting rubber, and lift off the bracket.

Undo the three bolts securing the engine bracket to the end of the cylinder head/block, and remove the bracket.

15 On models with a distributor, disconnect the wiring connector from the ignition HT coil.

If the cylinder head is to be dismantled for overhaul, remove the distributor as described in the relevant Sections of Chapter 5.

Disconnect the HT leads from the spark plugs, and remove the distributor cap and lead assembly. If the cylinder numbers are not already marked on the HT leads, number each lead, to avoid the possibility of the leads being incorrectly connected on refitting.

16 On models with a static (distributorless) ignition system, disconnect the wiring connector from the ignition HT coil. If the cylinder head is to be dismantled for overhaul, remove the ignition HT coil as described in Chapter 5. Note that the HT leads should be disconnected from the spark plugs instead of the coil, and the coil and leads removed as an assembly. If the cylinder numbers are not already marked on the HT leads, number each lead, to avoid the possibility of the leads being incorrectly connected on refitting.

17 Working in the reverse of the tightening sequence, progressively slacken the ten cylinder head bolts by half a turn at a time, until all bolts can be unscrewed by hand.

Remove the bolts along with their washers, noting the correct location of the spacer fitted to the front left-hand bolt.

18 With all the cylinder head bolts removed, the joint between the cylinder head and gasket and the cylinder block/crankcase must now be broken without disturbing the wet liners. Care must be taken on 1508 cc, 1761 cc and 1905 cc engines to prevent displacement of the wet liners; although these liners are better-located and sealed than some wet-liner engines, there is still a risk of coolant and foreign matter leaking into the sump if the cylinder head is lifted carelessly. If care is not taken and the liners are moved, there is also a possibility of the bottom seals being disturbed, causing leakage after refitting the head. This problem does not apply to 1998 cc engines as the liners are conventional and form part of the cylinder block.

19 To break the joint, obtain two L-shaped metal bars which fit into the cylinder head bolt holes, and gently rock the cylinder head free towards the front of the car (see Part A). On wet liner engines, do not try to swivel the head on the cylinder block/crankcase; it is located by dowels, as well as by the tops of the liners.

20 When the joint is broken, lift the cylinder head away. Seek assistance if possible, as it is a heavy assembly, especially if it is complete with the manifolds. Remove the gasket from the top of the block, noting the two locating dowels. If the locating dowels are a loose fit, remove them and store them with the head for safe-keeping. Do not discard the gasket; it will be needed for identification purposes.

21 On wet liner engines, do not attempt to turn the crankshaft with the cylinder head removed, otherwise the wet liners may be displaced. Operations that require the crankshaft to be turned (eg cleaning the piston crowns), should only be carried out once the cylinder liners are firmly clamped in position. In the absence of the special Peugeot liner clamps, the liners can be clamped in position as follows. Use large flat washers positioned underneath suitablelength bolts, or temporarily refit the original head bolts, with suitable spacers fitted to their shanks (see illustration).

12.21 Cylinder liners clamped in position using suitable bolts and large flat
12.21 Cylinder liners clamped in position using suitable bolts and large flat washers

22 If the cylinder head is to be dismantled for overhaul, remove the camshaft as described in Section 10, then refer to Part C of this Chapter.

1905 cc 16-valve engines 23 Remove the cylinder head cover as described in Section 4. Also remove the air cleaner inlet ducting.

24 Unbolt the plastic cover from over the power steering pump drive pulley.

25 Disconnect the drivebelt from the power steering drive pulley with reference to Chapter 1.

26 Unscrew the bolt and remove the pulley from the end of the exhaust camshaft.

27 Identify all wiring connections on the cylinder head then disconnect them. Also disconnect the coolant hoses from the head.

28 Remove the ignition coil as described in Chapter 5.

29 Remove the inlet manifold as described in Chapter 4. To prevent damage to the radiator, position a piece of cardboard over it. On models with air conditioning, disconnect the associated wiring from the inlet manifold.

30 Working as described in Chapter 4, disconnect the exhaust system front pipe from the manifold.

31 Place a jack beneath the engine, with a block of wood on the jack head. Raise the jack until it is supporting the weight of the engine.

32 Remove the right-hand engine mounting bracket with reference to Section 18.

33 Remove the timing belt as described in Section 7.

34 Working in the reverse of the tightening sequence, progressively slacken the ten cylinder head bolts by half a turn at a time, until all bolts can be unscrewed by hand.

Remove the bolts along with their washers, noting the correct location of the spacer fitted to the front left-hand bolt.

35 Release the end of the timing belt cover from the coolant pump using a screwdriver.

36 With all the cylinder head bolts removed, the joint between the cylinder head and gasket and the cylinder block/crankcase must now be broken without disturbing the wet liners. Care must be taken to prevent displacement of the wet liners. Although these liners are better-located and sealed than some wet-liner engines, there is still a risk of coolant and foreign matter leaking into the sump if the cylinder head is lifted carelessly. If care is not taken and the liners are moved, there is also a possibility of the bottom seals being disturbed, causing leakage after refitting the head.

37 To break the joint, obtain two L-shaped metal bars which fit into the cylinder head bolt holes, and gently rock the cylinder head free towards the front of the car (see Part A). Do not try to swivel the head on the cylinder block/crankcase; it is located by dowels, as well as by the tops of the liners. Take care not to damage the oil supply tubes when inserting the metal bars - if necessary remove the tubes first.

38 When the joint is broken, lift the cylinder head away. Seek assistance if possible, as it is a heavy assembly. Remove the gasket from the top of the block, noting the two locating dowels. If the locating dowels are a loose fit, remove them and store them with the head for safe-keeping. Do not discard the gasket; it will be needed for identification purposes.

39 Do not attempt to turn the crankshaft with the cylinder head removed, otherwise the wet liners may be displaced. Operations that require the crankshaft to be turned (eg cleaning the piston crowns), should only be carried out once the cylinder liners are firmly clamped in position. In the absence of the special Peugeot liner clamps, the liners can be clamped in position as follows. Use large flat washers positioned underneath suitablelength bolts, or temporarily refit the original head bolts, with suitable spacers fitted to their shanks.

40 If the cylinder head is to be dismantled for overhaul, remove the camshafts as described in Section 10, then refer to Part C of this Chapter.

1998 cc 16-valve engines 41 The procedure is similar to that for the 1905 cc 16-valve engine described above, except for the following.

a) Where necessary remove both camshafts at the beginning of the procedure as described in Section 10.

b) When removing the inlet manifold, disconnect the ACAV assembly with reference to Chapter 4.

c) Unbolt the oil dipstick tube from the cylinder head.

d) The 1998 cc 16-valve engine has dry liners, and therefore all references to, and precautions for, wet liners can be ignored.

Preparation for refitting 42 The mating faces of the cylinder head and cylinder block/crankcase must be perfectly clean before refitting the head. Use a hard plastic or wooden scraper to remove all traces of gasket and carbon; also clean the piston crowns. On wet liner engines, refer to paragraph 36 before turning the engine. Take particular care on these models, as the soft aluminium alloy is easily damaged. On all models, make sure that the carbon is not allowed to enter the oil and water passages - this is particularly important for the lubrication system, as carbon could block the oil supply to the engines components. Using adhesive tape and paper, seal the water, oil and bolt holes in the cylinder block/crankcase. To prevent carbon entering the gap between the pistons and bores, smear a little grease in the gap. After cleaning each piston, use a small brush to remove all traces of grease and carbon from the gap, then wipe away the remainder with a clean rag. Clean all the pistons in the same way.

43 Check the mating surfaces of the cylinder block/crankcase and the cylinder head for nicks, deep scratches and other damage. If slight, they may be removed carefully with a file, but if excessive, machining may be the only alternative to renewal. If warpage of the cylinder head gasket surface is suspected, use a straight-edge to check it for distortion.

Refer to Part C of this Chapter if necessary.

44 On wet liner engines, check the cylinder liner protrusion as described in Part C of this Chapter.

Cylinder head gasket and head bolt information - 1580 cc, 1761 cc and 1905 cc models
45 On these models (aluminium cylinder block, wet-liner type engine) when purchasing a new cylinder head gasket, it is essential that a gasket of the correct thickness is obtained.

There are two different thicknesses available, the standard (1.2 mm) gasket which is fitted at the factory, and a slightly thicker (1.4 mm) gasket, for use once the head gasket face has been machined. The two gaskets can be identified as follows, by the holes in the tab on the left-hand end of the gasket.

46 With the gasket fitted the correct way up on the cylinder block, there will be a either a single hole, or series of holes, punched in the tab on the left-hand end of the gasket. The standard (1.2 mm) gasket has only one hole punched in it; the slightly thicker (1.4 mm) gasket has either two or three holes punched in it, depending on its manufacturer. Identify the gasket type, and ensure that the new gasket obtained is of the correct thickness. If there is any doubt as to which gasket is fitted, take the old gasket along to your Peugeot dealer, and have the dealer confirm the gasket type.

47 Check the condition of the cylinder head bolts, and particularly their threads, whenever they are removed. Wash the bolts in a suitable solvent, and wipe them dry. Check each bolt for any sign of visible wear or damage, renewing them if necessary. Measure the length of each bolt (without the washer fitted), from the underside of its head to the end of the bolt. If all bolts are less than 176.5 mm, they may be re-used. However, if any one bolt is longer than the specified length, all of the bolts should be renewed as a complete set.

Considering the stress which the cylinder head bolts are under, it is hightly recommended that they are renewed, regardless of their apparent condition.

Cylinder head gasket and head bolt information - 1998 cc 8-valve and 16-valve models
48 On 1998 cc models (cast-iron cylinder block without separate liners) there is only one thickness of head gasket available. The holes described above are still punched into the left-hand end of the gasket, but are of little importance, as they only identify the gasket manufacturer.

49 Check the condition of the cylinder head bolts, and particularly their threads, whenever they are removed. Wash the bolts in a suitable solvent, and wipe them dry. Check each bolt for any sign of visible wear or damage, renewing them if necessary. Measure the length of each bolt (without the washer fitted), from the underside of its head to the end of the bolt. If all bolts are less than 122.0 mm, they may be re-used. However, if any one bolt is longer than the specified length, all of the bolts should be renewed as a complete set.

Considering the stress which the cylinder head bolts are under, it is hightly recommended that they are renewed, regardless of their apparent condition.

Refitting
50 Wipe clean the mating surfaces of the cylinder head and cylinder block/crankcase.

Check that the two locating dowels are in position at each end of the cylinder block/crankcase surface. Where applicable, remove the cylinder liner clamps.

51 Position a new gasket on the cylinder block/crankcase surface, ensuring that its identification holes and tongue are at the lefthand end of the gasket.

8-valve engines
52 Where removed refit the camshaft (Section 10), then check that the crankshaft pulley and camshaft sprocket are still locked in position with their respective pins. With the aid of an assistant, carefully refit the cylinder head assembly to the block, aligning it with the locating dowels.

53 Apply a smear of grease to the threads, and to the underside of the heads, of the cylinder head bolts. Peugeot recommend Molykote G.RAPID PLUS grease (available from your Peugeot dealer); in the absence of the specified grease, any good-quality highmelting- point grease may be used.

54 Carefully enter each bolt and washer into its relevant hole (do not drop it in) and screw it in finger-tight, not forgetting to fit the spacer to the front left-hand bolt.

55 Working progressively and in the sequence shown, tighten the cylinder head bolts to their stage 1 torque setting, using a torque wrench and suitable socket (see illustration).

12.55 Cylinder head bolt tightening sequence
12.55 Cylinder head bolt tightening sequence

56 On 1508 cc, 1761 cc and 1905 cc engines, working bolt by bolt and in the specified sequence, fully slacken the bolt then tighten it to its stage 2 torque setting followed by its stage 3 angle. It is recommended that an angle-measuring gauge is used during the stage 3 tightening, to ensure accuracy. If a gauge is not available, use white paint to make alignment marks between the bolt head and cylinder head prior to tightening; the marks can then be used to check that the bolt has rotated sufficiently.

57 On 1998 cc engines, working in the correct sequence tighten all of the bolts to the stage 2 torque. With all the bolts at the stage 2 torque, angle-tighten the bolts to the stage 3 angle in the correct sequence using the gauge described in the previous paragraph.

58 Once the cylinder head bolts are correctly tightened, fill the four oil reservoir holes in the cylinder head (below the camshaft) with fresh engine oil.

59 Reconnect the wiring connector to the ignition HT coil. Otherwise, if the head was stripped for overhaul, refit the HT coil or distributor (as applicable), as described in Chapter 5.

60 Refit and tension the timing belt with reference to Section 8.

61 Refit the right-hand engine mounting and tighten the bolts to the specified torque. The jack can then be removed from under the engine.

62 The remaining procedure is a reversal of removal noting the following points.

a) Ensure that all wiring is correctly routed, and that all connectors are securely reconnected to the correct components.

b) Ensure that the coolant hoses are correctly reconnected, and that their retaining clips are securely tightened.

c) Ensure that all vacuum/breather hoses are correctly reconnected.

d) Refit the cylinder head cover as described in Section 4.

e) Reconnect the exhaust system to the manifold, refit the air cleaner housing and ducts, and adjust the accelerator cable, as described in Chapter 4. If the manifolds were removed, refit these as described in Chapter 4.

f) On completion, refill the cooling system as described in Chapter 1, and reconnect the battery.

1905 cc 16-valve engines 63 Where removed refit the camshafts (Section 10), then check that the crankshaft pulley and camshaft sprockets are still locked in position with their respective pins. With the aid of an assistant, carefully refit the cylinder head assembly to the block, aligning it with the locating dowels.

64 Apply a smear of grease to the threads, and to the underside of the heads, of the cylinder head bolts. Peugeot recommend the use of Molykote G.RAPID PLUS grease (available from your Peugeot dealer); in the absence of the specified grease, any goodquality high-melting-point grease may be used.

65 Carefully enter each bolt and washer into its relevant hole (do not drop it in) and screw it in finger-tight, not forgetting to fit the spacer to the front left-hand bolt.

66 Working progressively and in the sequence shown, tighten the cylinder head bolts to their stage 1 torque setting, using a torque wrench and suitable socket.

67 Working bolt by bolt and in the specified sequence, fully slacken the bolt then tighten it to its stage 2 torque setting followed by its stage 3 angle. It is recommended that an angle-measuring gauge is used during the stage 3 tightening, to ensure accuracy. If a gauge is not available, use white paint to make alignment marks between the bolt head and cylinder head prior to tightening; the marks can then be used to check that the bolt has rotated sufficiently.

68 Refit and tension the timing belt with reference to Section 8.

69 Refit the right-hand engine mounting and tighten the bolts to the specified torque. The jack can then be removed from under the engine.

70 The remaining procedure is a reversal of removal noting the following points.

a) Ensure that all wiring is correctly routed, and that all connectors are securely reconnected to the correct components.

b) Ensure that the coolant hoses are correctly reconnected, and that their retaining clips are securely tightened.

c) Ensure that all vacuum/breather hoses are correctly reconnected.

d) Refit the cylinder head cover as described in Section 4.

e) Reconnect the exhaust system to the manifold, refit the air cleaner housing and ducts, and refit the manifolds as described in Chapter 4.

f) Reconnect the power steering drive pulley and drivebelt with reference to Chapter 1.

g) On completion, refill the cooling system as described in Chapter 1, and reconnect the battery.

1998 cc 16-valve models
71 The procedure is similar to that for the 1905 cc 16-valve engine described above, but refer also to paragraph 40.


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