Mazda Trucks 1987-1993 Repair Guide

Cylinder Head

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REMOVAL AND INSTALLATION



2.2L Engine

See Figures 1 and 2

  1. Relieve the fuel system pressure if an injected model. Disconnect the negative battery cable and drain the cooling system.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to 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. Disconnect the spark plug wires and remove the spark plugs.
  2.  
  3. Disconnect the accelerator cable. If equipped with automatic transmission, disconnect the throttle cable.
  4.  
  5. Remove the air intake pipe.
  6.  
  7. Remove the air cleaner and fuel hose. Cover the fuel hose to prevent leakage, if equipped with a carburetor. If injected, remove the air intake hose. If equipped with a carburetor, remove the fuel pump.
  8.  


CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

  1. Remove the upper radiator hose, water by-pass hose, heater hose, and brake vacuum hose.
  2.  
  3. Remove the 3-way and EGR solenoid valve assemblies.
  4.  
  5. Disconnect the engine harness connector and ground wire.
  6.  
  7. Remove the vacuum chamber and exhaust manifold insulator.
  8.  
  9. Remove the EGR pipe and exhaust pipe.
  10.  
  11. Remove the exhaust manifold.
  12.  
  13. Remove the intake manifold bracket and the intake manifold.
  14.  
  15. Remove the distributor.
  16.  
  17. Loosen the air conditioning compressor and bracket, position it off to the side and tie it out of the way. Do not disconnect the refrigerant lines!
  18.  
  19. Remove the upper timing belt cover and the timing belt tensioner spring.
  20.  
  21. To remove the timing belt, perform the following:
    1. Rotate the crankshaft so that the 1 on the camshaft pulley is aligned with the timing mark on the front housing.
    2.  
    3. When timing marks are aligned, loosen the timing belt tensioner lock bolt. Pull the tensioner as far out as will go and then temporarily tighten the lock bolt to hold it there.
    4.  
    5. Lift the timing belt from the camshaft pulley and position it out of the way.
    6.  

  22.  
  23. Remove the cylinder head cover and cover gasket.
  24.  



Click image to see an enlarged view

Fig. Fig. 1: Cylinder head bolt removal sequence

  1. Loosen the cylinder head bolts in the proper sequence and remove the cylinder head and head gasket.
  2.  
  3. Once the cylinder head has been removed, it should be cleaned and inspected before installing it onto the engine or being replaced. Refer to the "Engine Reconditioning" later in this section.
  4.  

To install:
  1. Position a new head gasket on the cylinder block and install the cylinder head. Apply oil to the threads and seat faces of the cylinder head bolts and install.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Cylinder head bolt tightening sequence

  1. Tighten the cylinder head bolts in 2-3 steps in the proper sequence. The final torque specification is 59-64 ft. lbs. (80-86 Nm).
  2.  
  3. Apply silicone sealer to each side of the front and rear camshaft bearing caps where the cap meets the cylinder head. Install the rocker arm cover.
  4.  
  5. Install the timing belt and tensioner. Install the timing belt front cover.
  6.  
  7. Install the intake and exhaust manifolds.
  8.  
  9. Install the upper radiator and water by-pass hoses. If carburetor equipped, install the secondary air pipe.
  10.  
  11. Install the distributor. Install the spark plugs and connect the spark plug wires.
  12.  
  13. Connect all vacuum hoses and electrical connectors. Connect the heater hoses and the brake vacuum hose.
  14.  
  15. If equipped, install the fuel pump. Connect the fuel lines.
  16.  
  17. Install the cooling fan and shroud.
  18.  
  19. Connect the accelerator cable. Install the air cleaner or air intake hose.
  20.  
  21. Install the splash shield. Connect the negative battery cable.
  22.  
  23. Fill and bleed the cooling system. Run the engine and check for leaks.
  24.  
  25. Check and adjust the ignition timing.
  26.  

2.6L Engine (1987-88)

See Figures 3 and 4

  1. Relieve fuel system pressure, if injected. Disconnect the negative battery cable. Drain the cooling system.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to 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. Remove the air cleaner assembly.
  2.  
  3. Remove the exhaust manifold.
  4.  
  5. Remove the water by-pass pipe. Disconnect all necessary vacuum hoses and electrical connectors. Disconnect the fuel lines.
  6.  


CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

  1. Remove the carburetor and intake manifold. Remove the distributor.
  2.  
  3. Remove the rocker arm cover. Remove the rocker arm and shaft assembly, leaving the bolts in place in the shaft to keep the assembly together. Install hydraulic lash adjuster holder tools 49 U012 001 or equivalent to keep the adjusters from falling.
  4.  
  5. Hold the crankshaft pulley bolt with a wrench to keep it from turning, then remove the camshaft sprocket bolt. Remove the camshaft. With the camshaft sprocket and timing chain meshed together, place the sprocket on the sprocket holder.
  6.  

Do not rotate the engine with the camshaft removed. Once the cylinder head is removed, do not allow the sprocket to fall from the sprocket holder.

  1. Remove the cylinder head-to-timing chain case bolts.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Cylinder head bolt removal sequence

  1. Loosen the cylinder head bolts in 2-3 steps in the proper sequence. Remove the bolts and remove the cylinder head.
  2.  

Clean all gasket mating surfaces.

  1. Once the cylinder head has been removed, it should be cleaned and inspected before installing it onto the engine or being replaced. Refer to the "Engine Reconditioning" later in this section.
  2.  

To install:
  1. Apply a thin coat of sealer to the cylinder block and timing chain cover contact surfaces, install a new head gasket and the cylinder head. Do not apply sealer to the cylinder head gasket.
  2.  



Click image to see an enlarged view

Fig. Fig. 4: Cylinder head bolt tightening sequence

  1. Apply oil to the threads and seat faces of the cylinder head bolts and install. With the engine cold, tighten the cylinder head bolts, in sequence in 2-3 steps. Final torque on bolts 1-10 should be 65-72 ft. lbs. (88-98 Nm) and on bolts 11 and 12, 11-16 ft. lbs. (15-22 Nm).
  2.  
  3. Apply engine oil to the camshaft journals and install the camshaft, aligning the dowel pin with the camshaft sprocket. Install the distributor drive gear and the lock bolt. Tighten the lock bolt by hand only at this time.
  4.  
  5. Coat the circular packing with sealant and install in the rear of the cylinder head. Install the rocker arms/shafts assembly and tighten the mounting bolts, in sequence, to 14-15 ft. lbs. (19-20 Nm) except for the No. 5 bearing cap rear bolt, which should be tightened to 15-20 ft. lbs. (20-26 Nm).
  6.  
  7. Tighten the distributor drive gear/camshaft sprocket lock bolt to 36-43 ft. lbs. (49-58 Nm).
  8.  
  9. Remove the hydraulic lash adjuster holders. Adjust the jet valve clearance.
  10.  
  11. Install the half-circle packing in the front of the cylinder head and apply sealer across the top of the packing and on both sides of the packing on the cylinder head. Install the rocker arm cover and tighten the bolts to 43-61 inch lbs. (5-7 Nm).
  12.  
  13. Install the remaining components. Fill and bleed the cooling system. Run the engine and check for leaks. Check and adjust the ignition timing.
  14.  

2.6L Engine (1989-93)

See Figures 5 and 6

  1. Properly relieve the fuel system pressure.
  2.  


CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly.
  4.  
  5. Drain the coolant.
  6.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to 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. Position the engine at TDC on the compression stroke so that all the pulley matchmarks are aligned.
  2.  
  3. Remove the accelerator cable. Remove the air intake pipe and resonance chamber.
  4.  
  5. Remove the accessory drive belts and AC belt idler.
  6.  
  7. Remove the upper radiator hose.
  8.  
  9. Remove the brake vacuum hose.
  10.  
  11. Remove the spark plug wires.
  12.  
  13. Remove the spark plugs.
  14.  
  15. Remove the oil cooler coolant hose.
  16.  
  17. Remove the canister hose.
  18.  
  19. Remove the fuel lines.
  20.  
  21. Disconnect the oxygen sensor.
  22.  
  23. Remove the solenoid valves.
  24.  
  25. Disconnect the emissions harness.
  26.  
  27. Remove the rocker cover. Check to ensure the engine is set on TDC. The timing mark on the camshaft sprocket should be 90 degrees to the right, parallel to the top of the cylinder head. Make sure the yellow crankshaft pulley timing mark is aligned with the indicator pin.
  28.  
  29. Remove the distributor. Do not rotate the engine after distributor removal.
  30.  
  31. Hold the crankshaft pulley with a suitable tool and remove the distributor drive gear/camshaft pulley retaining bolt and the drive gear. Remove the upper timing cover assembly.
  32.  
  33. Push the timing chain adjuster sleeve in towards the left, and insert a pin (2mm [0.0787 in.] diameter by 45mm [1.77 in.] long) into the lever hole to hold it in place.
  34.  
  35. Wire the chain to the pulley and remove the pulley from the camshaft. Do not allow the sprocket and chain to fall down into the engine and cause the chain to become disengaged from the crankshaft sprocket.
  36.  
  37. Remove the intake manifold bracket.
  38.  
  39. Disconnect the exhaust pipe.
  40.  



Click image to see an enlarged view

Fig. Fig. 5: Cylinder head bolt removal sequence

  1. Remove the 2 front head bolts.
  2.  
  3. Remove the remaining head bolts starting from the middle and working outward toward the ends of the head.
  4.  
  5. Lift off the head.
  6.  
  7. Discard the head gasket.
  8.  
  9. Once the cylinder head has been removed, it should be cleaned and inspected before installing it onto the engine or being replaced. Refer to the "Engine Reconditioning" later in this section.
  10.  

To install:
  1. Apply RTV sealer to the top front of the block as shown.
  2.  
  3. Place a new head gasket on the block.
  4.  
  5. Position the head on the block.
  6.  
  7. Clean the head bolts and apply oil to the threads.
  8.  



Click image to see an enlarged view

Fig. Fig. 6: Cylinder head bolt tightening sequence

  1. Tighten the head bolts, in 2 even steps, to 64 ft. lbs. (87 Nm).
  2.  
  3. Torque the two front bolts, to 17 ft. lbs. (23 Nm).
  4.  
  5. Place the camshaft pulley on the camshaft and tighten the bolt to to 95 inch lbs. (11 Nm).; the nut to 87 inch lbs. (10 Nm).
  6.  
  7. Connect the exhaust pipe.
  8.  
  9. Install the intake manifold bracket.
  10.  
  11. Install the upper timing cover assembly.
  12.  
  13. Install the distributor.
  14.  
  15. Install the rocker cover.
  16.  
  17. Connect the emissions harness.
  18.  
  19. Install the solenoid valves.
  20.  
  21. Connect the oxygen sensor.
  22.  
  23. Install the fuel lines.
  24.  
  25. Install the canister hose.
  26.  
  27. Install the oil cooler coolant hose.
  28.  
  29. Install the spark plugs.
  30.  
  31. Install the spark plug wires.
  32.  
  33. Install the brake vacuum hose.
  34.  
  35. Install the upper radiator hose.
  36.  
  37. Install the accessory drive belts.
  38.  
  39. Install the accelerator cable.
  40.  
  41. Fill the cooling system.
  42.  
  43. Install the air cleaner assembly.
  44.  
  45. Connect the negative battery cable.
  46.  

3.0L Engine

See Figures 7 and 8

  1. Position the engine at TDC on the compression stroke.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Remove the air cleaner assembly.
  8.  
  9. Drain the cooling system.
  10.  
  11. Remove the spark plug wires.
  12.  
  13. Remove the fresh air duct assembly.
  14.  
  15. Remove the cooling fan and radiator cowling.
  16.  
  17. Remove the drive belts.
  18.  
  19. Remove the air conditioning compresser idler pulley. If necessary, remove the compresser and position it to the side.
  20.  
  21. Remove the crankshaft pulley and baffle plate.
  22.  
  23. Remove the coolant bypass hose.
  24.  
  25. Remove the upper radiator hose.
  26.  
  27. Remove the timing belt cover assembly retaining bolts. Remove the timing belt cover assembly and gasket.
  28.  
  29. Turn the crankshaft to align the mating marks of the pulleys.
  30.  
  31. Remove the upper idler pulley.
  32.  
  33. Remove the timing belt. If reusing the belt be sure to mark the direction of rotation.
  34.  
  35. Disconnect and plug canister, brake vacuum and fuel hoses. If equipped with automatic transmission, disconnect the automatic transmission vacuum hose.
  36.  
  37. Remove the 3-way soleniod valve assembly and disconnect all engine harness connector and grounds.
  38.  
  39. If equipped with automatic transmission, remove the dipstick. Disconnect the required vacuum hoses. Disconnect the accelerator linkage.
  40.  
  41. Remove the distributor and the EGR pipe.
  42.  
  43. Remove the six extension manifolds. Remove the O-rings from the extension manifolds and purchase new ones. Remove the intake manifold by loosening the retaining bolts in the proper sequence.
  44.  
  45. Remove the cylinder head cover, gasket and seal washers.
  46.  
  47. Remove the center exhaust pipe insulator and pipe. Disconnect the exhaust manifold retaining bolts. Remove the exhaust manifold with insulator.
  48.  
  49. Remove the seal plate.
  50.  



Click image to see an enlarged view

Fig. Fig. 7: Cylinder head bolt removal sequence

  1. Remove the cylinder head retaining bolts in the proper sequence in 2 or 3 stages. Remove the cylinder head from the vehicle.
  2.  
  3. Once the cylinder head has been removed, it should be cleaned and inspected before installing it onto the engine or being replaced. Refer to the "Engine Reconditioning" later in this section.
  4.  
  5. Thoroughly clean the cylinder head bolts. After the bolts are cleaned, measure the length of each bolt and replace out of specifications bolts as required.

    Intake: 108mm
     
    Exhaust: 138mm Maximum
     
    Intake: 109mm
     
    Exhaust: 139mm
     

  6.  
  7. Check the oil control plug projection at the cylinder block. Projection should be 0.53-0.57mm. If correct, apply clean engine oil to a new O-ring and position it on the control plug.
  8.  

To install:
  1. Place the new cylinder head gasket on the left bank with the L mark facing up. Place the new cylinder head gasket on the right bank with the R mark facing up. Install the cylinder onto the block. Tighten the head bolts in the following manner:
    1. Coat the threads and the seating faces of the head bolts with clean engine oil.
    2.  

  2.  



Click image to see an enlarged view

Fig. Fig. 8: Cylinder head bolt tightening sequence

    1. Torque the bolts in the proper sequence to 14 ft. lbs. (19 Nm).
    2.  
    3. Paint a mark on the head of each bolt.
    4.  
    5. Using this mark as a reference, tighten the bolts in the proper sequence an additional 90°.
    6.  
    7. Repeat Step d.
    8.  

  1. Install the seal plate.
  2.  
  3. Install the exhaust manifold with insulator.
  4.  
  5. Connect the exhaust manifold retaining bolts.
  6.  
  7. Install the center exhaust pipe insulator and pipe.
  8.  
  9. Install the cylinder head cover, gasket and seal washers.
  10.  
  11. Install the intake manifold by loosening the retaining bolts in the proper sequence.
  12.  
  13. Install the O-rings from the extension manifolds.
  14.  
  15. Install the six extension manifolds.
  16.  
  17. Install the distributor and the EGR pipe.
  18.  
  19. If equipped with automatic transmission, install the dipstick. Connect the required vacuum hoses. Connect the accelerator linkage.
  20.  
  21. Install the 3-way soleniod valve assembly and connect all engine harness connector and grounds.
  22.  
  23. Connect the canister, brake vacuum and fuel hoses. If equipped with automatic transmission, connect the automatic transmission vacuum hose.
  24.  
  25. Install the timing belt.
  26.  
  27. Install the timing belt cover assembly and new gasket.
  28.  
  29. Install the upper radiator hose.
  30.  
  31. Install the coolant bypass hose.
  32.  
  33. Install the crankshaft pulley and baffle plate.
  34.  
  35. Install the compresser.
  36.  
  37. Install the air conditioning compresser idler pulley.
  38.  
  39. Install the accessory drive belts.
  40.  
  41. Install the cooling fan and radiator cowling.
  42.  
  43. Install the fresh air duct assembly.
  44.  
  45. Install the spark plug wires.
  46.  
  47. Fill the cooling system.
  48.  
  49. Install the air cleaner assembly.
  50.  
  51. Connect the negative battery cable.
  52.  

4.0L Engine

See Figure 9

  1. Relieve fuel system pressure. Disconnect the negative battery cable. Drain the cooling system (engine cold) into a clean container and save the coolant for reuse.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to 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. Disconnect the battery ground cable.
  2.  
  3. Remove the air cleaner.
  4.  
  5. Remove the upper and lower intake manifolds as described earlier.
  6.  
  7. If the left cylinder head is being removed:
    1. Remove the accessory drive belt.
    2.  
    3. Remove the air conditioning compressor.
    4.  
    5. Remove the power steering pump and bracket assembly. DO NOT disconnect the hoses. Tie the assembly out of the way.
    6.  
    7. Remove the spark plugs.
    8.  

  8.  
  9. If the right head is being removed:
    1. Remove the accessory drive belt.
    2.  
    3. Remove the alternator and bracket.
    4.  
    5. Remove the EDIS ignition coil and bracket.
    6.  
    7. Remove the spark plugs.
    8.  

  10.  
  11. Remove the exhaust manifold(s).
  12.  
  13. Remove the rocker arm covers as previously described.
  14.  
  15. Remove the rocker shaft assembly.
  16.  
  17. Remove the pushrods, keeping them in order so they may be installed in their original locations.
  18.  
  19. Loosen the cylinder head attaching bolts in reverse of the torque sequence, then remove the bolts and discard them. They cannot be re-used.
  20.  
  21. Lift off the cylinder head(s).
  22.  
  23. Remove and discard the old cylinder head gasket(s).
  24.  
  25. Once the cylinder head has been removed, it should be cleaned and inspected before installing it onto the engine or being replaced. Refer to the "Engine Reconditioning" later in this section.
  26.  

To install:
  1. Lightly oil all bolt and stud bolt threads except those specifying special sealant. Position the new head gasket(s) on the cylinder block, using the dowels for alignment. The dowels should be replaced if damaged.
  2.  

The cylinder head(s) and intake manifold are torqued alternately and in sequence, to assure a correct fit and gasket crush.

  1. Position the cylinder head(s) on the block.
  2.  
  3. Apply a bead of RTV silicone gasket material to the mating joints of the head and block at the 4 corners. Install the intake manifold gasket and again apply the sealer.
  4.  

This sealer sets within 15 minutes, so work quickly!

  1. Install the lower intake manifold and intsall the bolts and nuts for the manifold and head(s). Tighten all fasteners finger-tight.
  2.  



Click image to see an enlarged view

Fig. Fig. 9: Cylinder head bolt tightening sequence

  1. Tighten the intake manifold fasteners, in sequence, to 36-72 inch lbs. (4-8 Nm).
  2.  


WARNING
Do not re-use the old head bolts. ALWAYS use new head bolts!

  1. Torque the head bolts, in sequence, to 59 ft. lbs. (80 Nm).
  2.  
  3. Tighten the intake manifold fasteners, in sequence, to 6-11 ft. lbs. (8-15 Nm).
  4.  
  5. Tighten the head bolts, in sequence, an additional 80-85 DEGREES tighter. 85 degrees is a little less than 1 / 4 turn. 1 / 4 turn would equal 90 degrees.
  6.  
  7. Torque the intake manifold fasteners, in sequence, to 11-15 ft. lbs. (15-20 Nm).; then, in sequence, to 15-18 ft. lbs. (20-24 Nm).
  8.  
  9. Dip each pushrod in heavy engine oil then install the pushrods in their original locations.
  10.  
  11. Install the rockerarm/shaft assembly(ies).
  12.  
  13. Apply another bead of RTV sealer at the 4 corners where the intake manifold and heads meet.
  14.  
  15. Install the rocker covers, using new gaskets coated with sealer.
  16.  
  17. Install the upper intake manifold.
  18.  
  19. Install the exhaust manifold(s).
  20.  
  21. Install the spark plugs and wires.
  22.  
  23. If the left head was removed, install the power steering pump, compressor and drive belt.
  24.  
  25. If the right head was removed, install the EDIS coil and bracket, alternator and bracket, and the drive belt.
  26.  
  27. Install the air cleaner.
  28.  
  29. Fill the cooling system.
  30.  

At this point, it's a good idea to change the engine oil. Coolant contamination of the engine oil often occurs during cylinder head removal.

  1. Connect the battery ground cable.
  2.  
  3. Start the engine and check for leaks.
  4.  

 
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