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See Figure 13
Fig. 13: Cylinder head bolt tightening sequence-3.8L engine
Disconnect the negative battery cable.
Drain and recycle the engine coolant.
Remove the air cleaner assembly.
Remove the cowl top vent panel.
Rotate the tensioner clockwise and remove the accessory drive belt.
If the front cylinder head is being removed, perform the following:
Remove the oil filler cap.
Remove the A/C compressor mounting bracket and set A/C compressor aside with refrigerant lines still connected.
Remove the power steering pump and bracket. Leave power steering hoses connected and place the pump aside in the engine compartment.
Remove the alternator and alternator mounting bracket.
If the rear cylinder head is being removed, perform the following:
Remove the accessory drive belt tensioner.
Remove the PCV valve
Remove the power steering line bracket.
Remove the tensioner bracket.
Remove the coil pack assembly.
Remove the upper intake manifold.
Remove the valve cover.
Properly relieve the fuel system pressure.
Remove the fuel charging assembly.
Remove the lower intake manifold.
Remove the exhaust manifolds.
Pushrods must be installed in their original position. Note pushrod location during removal.
Loosen rocker arm seat retaining bolts and remove the pushrods.
Remove cylinder head bolts.
Lift cylinder head from engine block and discard gaskets.
The cylinder head should be cleaned and inspected by a competent machinist prior to installation. For general cylinder head inspection and overhaul procedures, refer to Engine Reconditioning in this section.
Lightly oil all bolt and stud bolt threads before installation.
Clean all gasket mating surfaces thoroughly.
Position new head gaskets on the cylinder block, noting the UP position on the gasket face, using the dowels in the engine block for alignment. If the dowels are damaged, they must be replaced.
Position the cylinder head on the cylinder block.
Lubricate cylinder head bolts with 50 weight oil and install. Tighten the cylinder head bolts in 3 steps following the proper torque sequence. The first step is 15 ft. lbs. (20 Nm), the second step is 29 ft. lbs. (40 Nm) and the third step is 37 ft. lbs. (50 Nm).
Do not loosen all of the cylinder head bolts at once. Only work on one bolt at a time or damage to the engine may occur.
In sequence, loosen the cylinder head bolt 2-3 turns and retighten in 2 steps.
On long bolts, the first step is 29-37 ft. lbs. (40-50 Nm). The second step is tighten additional 175-185 degrees.
On short bolts, the first step is 15-22 ft. lbs. (20-30 Nm). The second step is tighten additional 175-185 degrees.
Dip each pushrod end in engine assembly lubricant. Install the pushrods in their original position.
Lubricate all rocker arm components with engine assembly lubricant.
Rotate the engine clockwise until the valve tappet rests on the heel (base circle) of the camshaft lobe.
Install rocker arms, seats and bolts and tighten to 44 inch lbs. (5 Nm). After all rocker arms have been installed, final tighten all bolts to 22-29 ft. lbs. (30-40 Nm).
Install exhaust manifolds.
Install lower intake manifold.
Install fuel injection charging assembly.
Install valve covers with new gaskets. Tighten bolts to 71-97 inch lbs. (8-11 Nm).
Install upper intake manifold.
Install spark plugs and ignition wires.
Install the alternator and alternator mounting bracket.
Install the power steering pump and bracket
Install the A/C compressor mounting bracket
Install the oil filler cap.
Install the coil pack assembly.
Install the tensioner bracket.
Install the power steering line bracket.
Install the PCV valve
Install the accessory drive belt tensioner.
Install the cowl top vent panel.
Install the air cleaner assembly.
Fill and bleed the cooling system.
Connect the negative battery cable.
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