PULLEY GP-FAN DRIVE 7N3790 - Caterpillar

Introduction
Do not perform any procedure in this Special Instruction until you read this information and you understand this information.Reason for the New Head Gasket
Some issues have been occurring with the current head gasket on air compressors. The head gasket is allowing compressed air to enter the cooling system. New metal head gaskets are now used to prevent the compressed air from entering the coolant system.Procedure to Replace the Head Gasket
Table 1
Required Parts    
1     6L-1883 Gasket    
2     6V-6609 O-Ring Seal    
1     6V-1903 O-Ring Seal    
2     2M-9780 O-Ring Seal    
1     307-6209 Cylinder Head Kit    Note: The 307-6209 Cylinder Head Kit contains a new cylinder head assembly, a new head gasket, and six new cylinder head bolts.Cylinder Head Removal
Purge the air system to less than 620 kPa (90 psi).
Drain the vehicle's coolant system.
Disconnect the air and coolant lines from the fittings that mate on the compressor.
If the engine has a governor then remove the governor. Also remove the fittings that mate and the pressure relief valve on the head of the compressor. These parts will be used on new cylinder head assembly. Do not discard these parts.
Loosen the six head bolts. Remove the six head bolts and discard the bolts.Note: Note the orientation of the cylinder head ports to the engine.
Remove the cylinder head assembly from the cylinder block. If necessary, tap the head assembly lightly with a plastic mallet in order to assist loosening of the head assembly from the cylinder block.
Remove the gasket from the top of the cylinder block and discard the gasket.Cylinder Head Installation
Make sure that the top of the cylinder block is clean and dry.
Retrieve the new cylinder head gasket, cylinder head assembly and head bolts.
Oil the threads of the head bolts with 15W40.
Install two head bolts into the new cylinder head assembly.
Install the head gasket over the two head bolts until the gasket is flush with the bottom surface of the cylinder head assembly.
While holding the gasket against the cylinder head assembly and the two bolts against the cylinder head, orient the cylinder head and the head gasket assembly onto the cylinder block in the same orientation as the original cylinder head. Align the two head bolts in the thread holes of the cylinder block.
Hand tighten the two head bolts.
Install the four remaining head bolts and hand tighten the bolts.
Illustration 1 g01378326
The tightening sequence for the head bolts on the Air Compressor
Torque the six head bolts to the sequence in Illustration 1.
Tighten the bolts to 42 5 N m (30.9775 3.6878 lb ft) in order to burnish the bolts.
Loosen the six head bolts.
Tighten the six head bolts to 14 1 N m (10 1 lb ft) in the proper sequence in Illustration 1.
Tighten the six head bolts 120°. Loosen the bolts 2° in sequence. Tighten the bolts 4° in the proper sequence.
Illustration 2 g01378365
Tightening sequence for the Unloader bolts
Torque the unloader