GMC 12360424 Engine Cylinder Head (W/Valve)

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Take great care to see that the engine cools completely before you loosen the cylinder head bolts. In case of vehicles with a high mileage and during overhaul of an engine, it is preferable to check camshaft lobe heights before removing the cylinder heads. This will involve relieving fuel pressure, disconnecting the negative battery terminal, and removal of alternator and brackets, intake manifold, exhaust manifold, drivebelt tensioner bracket and power steering pump (if equipped). Also disconnect wires, hoses, fuel and vacuum lines from the cylinder head and label them for reinstallation. Disconnect spark plug wires then remove spark plugs. Take off rocker arm cover-rockers and pushrods. With a new head gasket; outline cylinders as well as bolt pattern on cardboard while loosening each cylinder head mounting bolt 1/4 turn at a time storing in cardboard holder. Carefully lift off the head tapping if it sticks onto a block of wood. Remove the Cylinder Head Gasket. For installation purposes; transfer external parts to the new cylinder head if needed , clean gasket surfaces , ensure clean threads on head bolts and engine block , apply gasket sealant to the new gasket (1987-1989 models)lower the cylinder head onto the engine then install bolts finger tight .Gradually tighten each bolt in 1/4 turn increments in recommended sequence to reach specified torque .While tightening mark each one in order to keep track of sequence used.Complete all remaining installation steps including refilling cooling system and changing oil filter.

This will involve cleaning the cylinder head and related valve train components. Clean the entire cylinder head with solvent as well as the rocker arms, pivot balls, nuts, pushrods, valve springs, spring seats, rotators, keepers and retainers as well as the rocker arm pivot stud threads. After heavy deposits have been scraped off from valves use a motorized wire brush to remove deposits from valve heads and stems. Examine the cylinder head for cracks, coolant leaks and warpage; inspect valve seats for damage. Measure the stem-to-guide clearance of each valve and examine each valve face/neck and stem for wear deformation, cracks pits and burns. Also measure the margin width on each valve and test spring lengths for wear. Inspect rocker arm faces, pivot contact areas, pivot balls pushrod ends and rocker arm studs as well as spring retainers, keepers and rotators. If any parts are damaged or worn excessively replace them. Finally reassemble valves in cylinder head if they are in poor condition with some being out of limits due to wear of all valve components.

Disconnect the negative battery cable in order to remove the cylinder head. Additionally, if necessary, the intake manifold should be removed and the mounting bolt of oil dipstick tube taken off. Label all wires, vacuum hoses and spark plug wires for reinstallation purposes before disconnecting them. After that, remove the rocker arm cover as well as detach the pushrods and rocker arms from the exhaust manifold. Take a new head gasket and outline cylinder heads on cardboard and then loosen each cylinder head mounting bolt gradually. When lifting the head(s) off the engine be careful not to damage mating surfaces. The mating surfaces should be clean for installation and use a gasket scraper to remove old material. Look for damage and chase threads in head bolt holes. Place the new gasket on dowel pins with caution when positioning it on block. Apply Teflon pipe sealant to bolt threads and undersides of bolt heads; then tighten bolts in recommended sequence. Finally, follow through with the rest of installation steps while changing oil as well as filter.

To start with, the negative battery cable must be disconnected. After draining the cooling system to prevent coolant from entering the engine's internal areas during head removal, remove the intake manifold. Next on is detaching the exhaust manifold, camshafts and housings. Take a new head gasket and outline cylinder and bolt patterns on a piece of cardboard that will serve as a holder for the head bolts; this is done by punching holes at the bolt locations indicating front of the engine on it; this will be useful for reference in future. Gradually loosen each of the head bolts by means of 1/4 turn, proceeding in order opposite to that used when tightening them down, store them to be reinstalled into this cardboard holder. Give a clear description of how to lift off the engine head, what to do if there is resistance and where to place it after removing it so that one could realize all cautionary measures are taken into account; even though there might be situations when lifting may require some forceful efforts then one would get needful information about protective measures you should take in order not to damage gasket sealing surfaces; finally protect your eyes. Before installing the gasket make sure both cylinder head and block mating surfaces are thoroughly cleaned using lacquer thinner or acetone applied through gasket scraper thus no oil is allowed to remain on these surfaces which will prevent it from sticking; inspection for damages must be performed on mating surfaces before filing them if necessary also use tap to chase threads out of corrosion in the head bolt holes. Place new gasket over dowel pins in block, carefully come down with head until transfer case is in position without effecting gasket installs bolts finger tight into their original locations followed by final torque. Then complete remaining installation steps backwards: fill cooling system again with antifreeze mixture (which should be prepared before), change oil and filter, run engine for leak checking and proper operation.

You can usually find new or rebuilt cylinder heads for most engines at dealerships or auto parts stores. Some special tools are required for disassembly and examination procedures, and spare parts may not be readily available, so it is more convenient and cost-effective for a backyard mechanic to purchase a replacement head (or two) rather than take the original(s) apart, examine them and then recondition them. Cylinder head disassembly includes taking out the intake valves, exhaust valves and other related components. For Quad-4 engine work, you must first get rid of the camshafts and housings before starting the cylinder head disassembly process. On a 2.0/2.2-liter four-cylinder or V6 engine, remove the rocker arm nuts, pivot balls, and rocker arms from the cylinder head studs. Label all parts or keep them until they can be replaced exactly where they were found. Before removing the valves, you should make arrangements for labeling and storage of these valves so that when they are put back in place again, it could be easy to identify each valve together with its relevant pieces. You will need to compress the springs on the first valve with a spring compressor to remove keepers. Gently release the valve spring compressor then take out the retainer followed by spring plus spring seat in case one is used. Remember that valve rotators are placed below springs on Quad-4 engines. Then remove oil seal from guide after pulling valve out of head. In case your valve binds in guide (will not pull through), simply push it back into head and deburr around keeper groove with a fine file or whetstone stone tool.Remember to repeat procedure for remaining valves.Once again remember this statement as you keep all parts per each valve in one area before restoring them back to their respective positions.After removing all valves including related items in an orderly manner then clean and inspect thoroughly.Prioritize finishing engine disassembly procedures first before commencing the cylinder head cleaning and inspection if you are undertaking total engine overhaul.

Before installing the valve seals during cylinder head reassembly, you should install the spring seats or valve rotators (if equipped).

The initial steps to remove the cylinder head are to disconnect the negative battery cable and drain the cooling system.

The intake manifold, exhaust manifolds, valve covers, and pushrods.

Loosen the cylinder head bolts in 1/4-turn increments.

After installing the cylinder head, you should finish by changing the oil and filter, adding coolant, running the engine, and checking for leaks.