Subaru Coupes/Sedans/Wagons 1985-1996 Repair Guide

Cylinder Head

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On some models, engine compartment room is limited, so it may be necessary to remove the engine to service the cylinder heads.

REMOVAL & INSTALLATION




CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze, and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

1.2L Engine

See Figures 1 and 2

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Fig. Fig. 1: Cylinder head bolt loosening sequence-1.2L engine



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Fig. Fig. 2: Cylinder head bolt tightening sequence-1.2L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the engine oil and coolant into suitable containers.
  4.  
  5. Remove the timing belt cover. Align the timing marks, then remove the timing belt and related components.
  6.  
  7. Remove the rocker arm cover.
  8.  
  9. Scribe alignment marks on the distributor and cylinder head, then remove the distributor.
  10.  
  11. Remove the exhaust manifold mounting bolts and separate the manifold from the cylinder head. Refer to the exhaust manifold procedure in this section.
  12.  
  13. Tag and disconnect the electrical harnesses and vacuum hoses attached to the intake manifold.
  14.  
  15. Remove the air suction valve and pipe, if equipped.
  16.  
  17. Remove the intake manifold assembly. Refer to the intake manifold procedure in this section.
  18.  
  19. Loosen the cylinder head mounting bolts in the correct sequence. DO NOT remove any of the bolts until all the bolts have been loosened.
  20.  
  21. Remove the cylinder head bolts.
  22.  
  23. Lift off the cylinder head and gasket from the engine block.
  24.  
  25. Clean all gasket material from both mating surfaces.
  26.  

To install:
  1. Install the cylinder head and gasket on the engine block.
  2.  
  3. Install the cylinder head bolts and tighten in three steps as follows:
    1. Tighten in sequence to 29 ft. lbs. (39 Nm).
    2.  
    3. Tighten in sequence to 43 ft. lbs. (59 Nm).
    4.  
    5. Tighten in sequence to 51 ft. lbs. (69 Nm).
    6.  

  4.  
  5. Install the intake manifold. Refer to the procedure in this section.
  6.  
  7. Install the air suction valve and pipe.
  8.  
  9. Connect the electrical harnesses and vacuum hoses to the intake manifold.
  10.  
  11. Install the exhaust manifold using a new gasket. Refer to the procedure in this section.
  12.  
  13. Align and install the distributor.
  14.  
  15. Install the rocker arm cover.
  16.  
  17. Install the timing belt components and timing belt cover.
  18.  
  19. Connect the negative battery cable.
  20.  
  21. Change the oil filter and fill the engine with clean oil. Fill the cooling system and bleed.
  22.  
  23. Start the vehicle and check for leaks. Adjust the ignition timing, if needed.
  24.  

1.6L, 1.8L and 2.7L engines

See Figures 3, 4, 5, 6, 7 and 8

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Fig. Fig. 3: Cylinder head assembly-1.6L and 1.8L engines



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Fig. Fig. 4: Cylinder head assembly-2.7L engine



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Fig. Fig. 5: Cylinder head bolt loosening sequence-1.6L and 1.8L engines



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Fig. Fig. 6: Cylinder head bolt tightening sequence-1.6L and 1.8L engines



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Fig. Fig. 7: Cylinder head bolt loosening sequence-2.7L engine



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Fig. Fig. 8: Cylinder head bolt tightening sequence-2.7L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the timing belt, belt cover and related components.
  4.  
  5. On turbocharged engines, remove the turbo cooling pipe together with the union screws and gaskets from the cylinder head.
  6.  
  7. Remove the camshaft cases, lash adjusters and related components.
  8.  
  9. On turbocharged engines, remove the EGR pipe.
  10.  
  11. Remove the plug attaching the EGR pipe to the cylinder head.
  12.  
  13. Remove the accessory drive belts, alternator and air conditioner compressor, if equipped. Remove the bolt attaching the alternator bracket to the cylinder head.
  14.  
  15. On vehicles without A/C, remove the bolt securing the adjusting bar to the cylinder.
  16.  
  17. On fuel injected engines, relieve the fuel system pressure.
  18.  
  19. Remove the bolts attaching the intake manifold to the cylinder head and remove the manifold.
  20.  
  21. Remove the bolt attaching the water bypass pipe bracket to the cylinder head.
  22.  
  23. Remove the spark plugs.
  24.  

On 2.7L engines, there are two types of cylinder head bolts used. Take note of cylinder head bolt arrangement as the bolts must be placed in their proper locations. Bolts number 1, 2, 9 and 13 measure 4.665 in. (118.5mm). All other bolts measure 5.217 in. (132.5mm).

  1. Loosen the cylinder head bolts in the proper sequence. Remove the cylinder heads from the block.
  2.  
  3. Clean all gasket material from the mating surfaces.
  4.  

To install:
  1. Inspect the cylinder head for warpage. Warpage should not exceed 0.0020 in. (0.05mm).
  2.  
  3. Install the cylinder head using a new gasket.
  4.  
  5. On the 1.6L and 1.8L engines, tighten the cylinder head bolts in three steps as follows:
    1. Tighten all bolts in sequence to 22 ft. lbs. (29 Nm).
    2.  
    3. Tighten all bolts in sequence to 43 ft. lbs. (59 Nm).
    4.  
    5. Tighten all bolts in sequence to 47 ft. lbs. (64 Nm).
    6.  

  6.  
  7. On the 2.7L engine, tighten the cylinder head bolts in four steps as follows:
    1. Tighten all bolts in sequence to 29 ft. lbs. (39 Nm).
    2.  
    3. Tighten all bolts in sequence to 47 ft. lbs. (64 Nm).
    4.  
    5. Loosen all bolts at least 90° in the reverse order of the tightening sequence.
    6.  
    7. Tighten all bolts in sequence to 44-50 ft. lbs. (60-68 Nm).
    8.  

  8.  
  9. Install the spark plugs. Install the water bypass pipe bracket.
  10.  
  11. Install the intake manifold and tighten the bolts to 13-16 ft. lbs. (18-22 Nm).
  12.  
  13. Install the alternator and bracket, air conditioner compressor, if equipped, and accessory drive belt.
  14.  
  15. On turbocharged engines, install the EGR pipe. Tighten the bolts to 23-27 ft. lbs. (31-37 Nm).
  16.  
  17. Install the camshaft cases, lash adjusters and related components.
  18.  
  19. On turbocharged engines, install the turbo cooling pipe. Tighten the bolts to 16-18 ft. lbs. (21-24 Nm).
  20.  
  21. Install the timing belt, belt cover and related components.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Adjust the valve lash, as required. Start the engine and allow it to reach operating temperature. Adjust the ignition timing.
  26.  
  27. Check for leaks, then test drive the vehicle.
  28.  

2.2L Engine

See Figures 9, 10, 11, 12, 13, 14 and 15

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Fig. Fig. 9: Cylinder head assembly-2.2L engine



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Fig. Fig. 10: Cylinder head bolt loosening sequence-2.2L engine



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Fig. Fig. 11: Cylinder head bolt tightening sequence-2.2L engine



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Fig. Fig. 12: Cover the intake manifold ports to keep out debris, then loosen the head bolts in order



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Fig. Fig. 13: Carefully remove the cylinder head. Notice how close it is to the side of the engine compartment



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Fig. Fig. 14: Remove the cylinder head gasket



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Fig. Fig. 15: Clean both mating surfaces with a suitable gasket scraper

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the drive belt.
  4.  
  5. Remove the power steering pump, alternator and bracket.
  6.  
  7. Remove the valve rocker cover.
  8.  
  9. Tag and disconnect the PCV hose and spark plug wires.
  10.  
  11. Remove the connector bracket attaching bolt.
  12.  
  13. Remove the crank angle and cam angle sensors.
  14.  
  15. Disconnect the oil pressure switch. Remove the knock sensor.
  16.  
  17. Disconnect the blow-by hose.
  18.  
  19. Relieve the fuel system pressure and disconnect the fuel pipes.
  20.  
  21. Remove the intake manifold and gasket. Remove the water pipe.
  22.  
  23. Remove the timing belt, camshaft sprocket and related components.
  24.  
  25. Remove the oil level gauge guide attaching bolt on the left cylinder head.
  26.  
  27. Remove the cylinder head bolts in the proper sequence. Leave bolts 1 and 3 installed loosely to prevent the cylinder head from falling.
  28.  
  29. Separate the cylinder head from the block, Use a plastic-faced hammer, if needed, to separate the head from the cylinder block.
  30.  
  31. Remove bolts 1 and 3. Remove the cylinder head and gasket.
  32.  
  33. Clean all gasket material from both mating surfaces.
  34.  

To install:
  1. Inspect the cylinder head for warpage. Warpage should not exceed 0.0020 in. (0.05mm).
  2.  
  3. Install the cylinder head on the block using a new gasket. Secure in place with the mounting bolts. Coat each bolts with clean engine oil, and hand-tighten.
  4.  
  5. Tighten the cylinder head bolts to the following specifications:
    1. Tighten all bolts in sequence to 22 ft. lbs. (29 Nm).
    2.  
    3. Tighten all bolts in sequence to 51 ft. lbs. (69 Nm).
    4.  
    5. Loosen all bolts by 180°, then loosen an additional 180°.
    6.  
    7. Tighten bolts 1 and 2 to 25 ft. lbs. (24 Nm) for non-turbo engines and 27 ft. lbs. (37 Nm) for turbo engines.
    8.  
    9. Tighten bolts 3, 4, 5 and 6 to 11 ft. lbs. (15 Nm) for non-turbo engines and 14 ft. lbs. (20 Nm) for turbo engines.
    10.  
    11. Tighten all bolts in sequence 80-90°.
    12.  
    13. Tighten all bolts in sequence an additional 80-90°.
    14.  

  6.  

Do not exceed 180° total tightening.

  1. Install the oil level gauge guide attaching bolt on the left cylinder head.
  2.  
  3. Install the timing belt, camshaft sprocket and related components.
  4.  
  5. Install the water pipe.
  6.  
  7. Install the intake manifold and tighten bolts to 21-25 ft. lbs. (28-34 Nm). Connect the fuel delivery pipes.
  8.  
  9. Connect the blow-by hose. Install the knock sensor.
  10.  
  11. Connect the oil pressure switch connector.
  12.  
  13. Install the crank and cam angle sensors.
  14.  
  15. Install the connector bracket attaching bolt.
  16.  
  17. Connect the spark plug wires. Connect the PCV hose.
  18.  
  19. Install the valve rocker cover and tighten bolts to 4 ft. lbs. (9 Nm).
  20.  
  21. Install the alternator, power steering pump and accessory drive belt.
  22.  
  23. Connect the negative battery cable. Start the engine and allow it to reach operating temperature. Check for leaks.
  24.  

2.5L Engine

See Figures 16 and 17

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Fig. Fig. 16: Cylinder head bolt loosening sequence-2.5L engine



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Fig. Fig. 17: Cylinder head bolt tightening sequence-2.5L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the V-belt.
  4.  
  5. Remove the power steering pump, alternator and bracket.
  6.  
  7. Remove the valve rocker cover.
  8.  
  9. Remove the connector bracket attaching bolt.
  10.  
  11. Remove the crank angle and cam angle sensors.
  12.  
  13. Remove the coolant filler tank.
  14.  
  15. Relieve the fuel system pressure and disconnect the fuel pipes.
  16.  
  17. Remove the intake manifold and gasket. Remove the water pipe.
  18.  
  19. Remove the timing belt, camshaft sprocket and related components.
  20.  
  21. Remove the oil level gauge guide attaching bolt on the left cylinder head.
  22.  
  23. Remove the cylinder head bolts in the proper sequence. Leave bolts 1 and 3 installed loosely to prevent the cylinder head from falling.
  24.  
  25. Separate the cylinder head from the block, Use a plastic-faced hammer, if needed.
  26.  
  27. Remove bolts 1 and 3. Remove the cylinder head and gasket.
  28.  
  29. Clean all gasket material from both mating surfaces.
  30.  

To install:
  1. Inspect the cylinder head for warpage. Warpage should not exceed 0.0020 in. (0.05mm).
  2.  
  3. Install the cylinder heads on the block using new gaskets. Secure in place with the mounting bolts. Coat each bolts with clean engine oil, and hand-tighten.
  4.  
  5. Tighten the cylinder head bolts to the following specifications:
    1. Tighten all bolts in sequence to 22 ft. lbs. (29 Nm).
    2.  
    3. Tighten all bolts in sequence to 51 ft. lbs. (69 Nm).
    4.  
    5. Loosen all bolts by 180°, then loosen an additional 180°.
    6.  
    7. Tighten bolts 1 and 2 to 25 ft. lbs. (24 Nm).
    8.  
    9. Tighten bolts 3, 4, 5 and 6 to 11 ft. lbs. (15 Nm).
    10.  
    11. Tighten all bolts in sequence by 80-90°.
    12.  
    13. Tighten all bolts in sequence an additional 80-90°.
    14.  

  6.  

Do not exceed 180° total tightening.

  1. Install the oil level gauge guide attaching bolt on the left cylinder head.
  2.  
  3. Install the timing belt, camshaft sprocket and related components.
  4.  
  5. Install the water pipe.
  6.  
  7. Install the intake manifold and tighten bolts to 21-25 ft. lbs. (28-34 Nm). Connect the fuel delivery pipes.
  8.  
  9. Connect the blow-by hose. Install the knock sensor.
  10.  
  11. Install the crank and cam angle sensors.
  12.  
  13. Install the connector bracket attaching bolt.
  14.  
  15. Connect the spark plug wires.
  16.  
  17. Install the valve rocker cover and tighten bolts to 4 ft. lbs. (9 Nm).
  18.  
  19. Install the alternator, power steering pump and accessory drive belt.
  20.  
  21. Connect the negative battery cable. Start the engine and allow it to reach operating temperature. Check for leaks.
  22.  

3.3L Engine

See Figures 18, 19 and 20

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Fig. Fig. 18: Cylinder head assembly-3.3L engine



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Fig. Fig. 19: Cylinder head bolt loosening sequence-3.3L engine



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Fig. Fig. 20: Cylinder head bolt tightening sequence-3.3L engine


CAUTION
Fuel injection systems remain under pressure after the engine has been turned OFF. Properly relieve fuel pressure before disconnecting any fuel lines. Failure to do so may result in fire or personal injury.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the intake and exhaust manifolds from the cylinder head. Refer to the needed procedures in this section.
  4.  
  5. Remove the timing belt and sprockets.
  6.  
  7. Remove both the camshafts.
  8.  
  9. Remove the oil dipstick and tube.
  10.  
  11. Remove the heater pipe.
  12.  
  13. Remove the cylinder head bolts in the proper sequence. DO NOT fully remove bolt number 5 or 8. One of these bolts should remain three of four threads into the block to prevent the cylinder head from falling.
  14.  
  15. Free the cylinder head from the block then remove the bolt left loosely in place. If the cylinder head will not come free easily, then tap the side of the head with a plastic-faced hammer.
  16.  
  17. Remove the cylinder head and gasket.
  18.  
  19. Clean all gasket material from both mating surfaces.
  20.  

To install:
  1. Install the cylinder head using a new gasket. Loosely install the cylinder head mounting bolts, coating each with clean engine oil.
  2.  
  3. Tighten the mounting bolts as follows:
    1. Tighten the bolts in sequence to 22 ft. lbs. (29 Nm).
    2.  
    3. Tighten the bolts in sequence to 51 ft. lbs. (69 Nm).
    4.  
    5. Back off all the bolts 180°.
    6.  
    7. Back off all bolts an additional 180°.
    8.  
    9. Tighten the bolts in sequence to 20 ft. lbs. (27 Nm).
    10.  
    11. Tighten bolts 1, 2, 3 and 4 an additional 90°.
    12.  
    13. Tighten bolts 5, 6, 7, and 8 to 33 ft. lbs. (44 Nm).
    14.  
    15. Tighten all bolts in sequence an additional 90°.
    16.  

  4.  
  5. Install the camshafts.
  6.  
  7. Install the heater pipe.
  8.  
  9. Install the oil dipstick and tube.
  10.  
  11. Connect the intake and exhaust manifolds to the cylinder head.
  12.  
  13. Install the timing belt and sprockets.
  14.  
  15. Connect the negative battery cable.
  16.  

CLEANING, INSPECTION AND RESURFACING



See Figure 21

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Fig. Fig. 21: Using a straightedge to check the cylinder head for signs of warpage

Invert the cylinder head and clean the carbon from the valve faces and combustion chambers. Use a permanent felt-tip marker and mark the valves for location.

Use a valve spring compressor and compress the valve springs. Lift out the keepers, release the valve spring compressor and remove the valve, spring and spring retainer. Place all parts removed in order so that they can be reinstalled on the same cylinder.

Remove the valves from the cylinder head. Chip away any remaining carbon from the valve heads, combustion chambers and ports. Use a rotary wire brush on an electric drill. Be sure that the deposits are actually removed, rather than burnished. Clean the valve faces with a wire wheel taking care not to remove the location numbering. Clean the cylinder head and component parts in an engine cleaning solvent.

Check the cylinder head for warpage by placing a straightedge across the gasket surface. Using feeler gauges, determine the clearance at the center of the straightedge. Measure across the diagonals, along the longitudinal centerline and across the cylinder head at several points. Should the warpage exceed 0.0020 in. (0.05mm) the cylinder head must be resurfaced. Be sure to observe the following grinding limits:



1.2L Engine: 0.008 in. (0.2mm)
 
1.6L, 1.8L and 2.7L Engines: 0.012 in. (0.3mm)
 
2.2L and 2.5L Engines: 0.004 in. (0.1mm)
 
3.3L Engine: 0.012 in. (0.3mm)
 

Clean the valve stems with lacquer thinner. Clean the valve guides using solvent and an expanding wire type valve guide cleaning brush. Insert the valve into the guide from which it was removed. With the valve slightly off of the valve seat, rock the valve face and stem back and forth. Excessive wobble means a worn guide, valve stem or both.

Measure the valve stems with a micrometer and compare the reading with the specifications to determine whether valve stem or guide wear is responsible for any excessive clearance. Replace or repair as necessary.

 
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