GM 12699617 Head Assembly, Cyl (W/ Vlv)

For this procedure it will be necessary to acquire a new set of 11 mm cylinder head bolts. Start with the process of clearing out pressure on the fuel system, next step is the removal of the cable on the negative terminal of the battery and the draining of the cooling system as well. The intake manifold must be either unbolted or sometimes pulled off and for 5.3L and 6.2L engines, fuel rail(s) also to be disconnected from cylinder head(s). Remove the cylinder head bolts, exhaust manifold(s) and untighten but do not remove the exhaust pipe(s) from the exhaust manifold(s), then remove the valve cover(s) and the rocker arms and pushrods and lay them in order to assemble it back. Subsequently, take out the coolant air bleed pipe aside, the alternator with its bracket and lower the ground strap from the back of the left cylinder head. As for the right cylinder head, on 6.0L models, it is necessary to remove the dipstick tube and to disconnect the ground cables at the front of the cylinder head. Back off the head bolts in a counter-clockwise direction, one quarter turn at a time, in the reverse order that they have been tightened unbolt until they are easily removable, observe different length and sizes of bolts needed for replacement with the new ones. If the head has warped set it on the blocks of wood or if you need to remove it fully, then use pry bar or long screwdriver and lift it gently off the engine and store it properly in order not to spoil gasket sealing surfaces. As for the cylinder heads mating surfaces, they should be absolutely free of any contaminants, thus making use of gasket removal solvents and a gasket scraper in order to remove the carbon and the residual gasket material. It is recommended that the block and head mating surfaces be inspected for any sign of damage, and if there are slight imperfections then take the same emery cloth while in cases of a lot of damages, it is recommended that one takes a machine. Use a tap to chase the threads in the head bolt holes and if you do not have access to a tap then clean it with brake cleaner and compressed air as the last resort. Install the new gaskets on top of those dowels in the block, then put the heads on the block gently without moving the gaskets and put a medium strength thread locking compound on the threads of the new 8mm head bolts. Use the new 11 mm head bolts and tighten them only with your hand to a light torque and then use the recommended pattern to tighten the bolts in four passages to reach the required torque. Replace coolant pipe with new gaskets and tighten bolt and to complete the process reversed manner of its removal. Last of all pour coolant, replace the oil and filter, switch on the engine and look for normal signs and any signs of leakage.

To remove cylinder heads start by draining the cooling system next remove the intake manifold, fuel rail from the cylinder head, crankcase valve covers, rocker arms and pushrods. Remove the exhaust manifold, where there is one, or to remove each of the manifold halves if there are two. If working on the right cylinder head, the drivebelt, the air conditioning compressor belt, the alternator, the idler pulley bolt and alternator and air conditioning compressor bracket should be detached from the engine. Subsequently, the spark plugs should be pulled out and the cylinder head bolts come less than 1/4-turn and be removed in the reverse pattern of the tightening sequences. Remove the bolts and acquire fresh ones to fix the equipment. Carefully remove the cylinder head(s) from the engine by placing a wooden block and lightly tapping it with a hammer if needed then, place the head on wooden blocks in order not to harm the gasket surfaces. To install you have to make sure that the mating surface of the cylinder heads and blocks are clean, use a gasket scraper and brake system cleaner to clean to remove carbon and old gasket material. To avoid cleaning debris in to the engine, cover the lifter valley with shop rags, and if there is debris that falls into the cylinders, use the vacuum cleaner to clean. Examine mating surfaces for nicks or deep scratches and, if required, take the assistance of a file or a machinist. Run the threads in the cylinder head bolt holes with a tap of the correct number. Align the new gaskets over the dowel pins in the block with the marks UP on top, but be very careful with composition type gaskets. Place the cylinder heads in the block properly keeping the gasket intact; then install the new cylinder head bolts and tightened them slightly with you fingers in the recommended sequence, and torque. The rest of the installation is just the opposite of removal. Last, replace the oil and the filter, refill the cooling system with the right type of coolant, and then engage the motor, looking out for signs of any leakage of oil or coolant.