Chevrolet 12575059 Cylinder Head Assembly

This should be done after the engine has reached room temperatures and after you have switched off the engine. Previously to cylinder head removal, on vehicles with high overall mileage and during the engine overhaul camshaft lobe height should be checked. First disarm the fuel system and open the negative terminal from the battery while the Theftlock audio system of the vehicle must be turned off. These are the next procedures; first, a gen3 alternator and brackets are pulled out and then the intake and exhaust manifolds. Remove the drivebelt tensioner bracket and the power steering pump; the component can be positioned to the side of the car without having to disconnect its hoses. Detaching any remaining wires, hoses, fuel and Vacuums lines to the cylinder head and tag them appropriately for reconnection. Pull the wires off the spark plugs and remove the spark plugs if you are able to label the wires beforehand. First of all, the valve cover, rocker arms and pushrods has to be unwired. To ensure that the head bolts shall not mix up, write and mark the cylinder and bolt pattern on a thin piece of cardboard, use this as a guide and remove the cylinder head mounting bolts slowly by ¼ turn until they can be removed and put in the corresponding holes in the cardboard. If needed use a hammer with a block of wood and gently lift the head off the engine to remove the cylinder head gasket. In case a new cylinder head is to be fitted then all the extra hardware from the old head must to be transffered to new head and a clean and proper gasket surface of the cylinder head as well as of the engine block should be free from any oily and dirty particles but should not be damaged. Check that the small threads of the head bolts and the large threads of the holes in the engine block are free from debris, and clean them with a die and tap if necessary. Put the gasket over the engine block dowel pins paying attention to the orienting marks and gently lowering the cylinder head on the engine block. Some of the bolts are tightened just enough so that they do not fully seat into place - this will later be tightened from where they are just a little loose, to 1/4 turn increments in the recommended pattern with the use of a special tool on the bolts where the tops have been marked with a felt-tip marker. The remaining process is the inverted procedure of the removal process and do not forget to fill the cooling system and replace the oil filter.

After disconnecting plug wires and exhaust manifolds, you should remove the rocker arm cover, rocker shaft assembly, and pushrods while keeping them in order.

If the clearance exceeds specifications, an oversize valve must be used after reaming the valve guide, which should be handled by a dealer or machine shop.

Ensure the cylinder head and block mating surfaces are impeccably clean for installation, using a gasket scraper and cleaning with lacquer thinner or acetone to prevent oil on the surfaces.

Apply moly-base grease to the rocker arm faces and the pivot balls. To install the rocker arms and pivots during cylinder head reassembly, place them on the cylinder head studs.

Allow the engine to cool completely.

For a 2.0/2.2-liter four-cylinder engine or a V6 engine, you should remove the rocker arm nuts, pivot balls, and rocker arms from the cylinder head studs before disassembling the cylinder head. It's important to label these parts or store them separately for reinstallation.

After disconnecting the battery cable, the intake manifold and the oil dipstick tube mounting bolt (if necessary) need to be removed.

Each valve should be inspected for wear, deformation, cracks, pits, and burns.

1. Loosen and remove all drive belts. 2. Tag and remove generator wires. 3. For vehicles with air conditioning, remove the compressor from the mounting bracket and position it out of the way with the hoses connected. 4. Remove the generator complete with bracket.

Specialized tools are necessary for dismantling and inspecting the heads, and replacement parts may not be readily available.

Disconnect the engine ground strap attached to the rear of one cylinder head.

Position the gasket over the engine block dowel pins with the bead up.

Install a new oil seal in the lower groove of the valve stem, ensuring it is flat and not twisted.

Tighten the rocker arm shaft assembly bolts gradually and torque-tighten them to specifications.

Thoroughly clean the threads on all cylinder head attaching bolts.

After removal, place the head on blocks of wood to protect the gasket surfaces.

Start the reassembly procedure with the installation of the spring seats or valve rotators (if equipped) before the valve seals.

Disconnect the negative battery cable from the battery, ensuring that the Theft lock audio system's lockout feature is turned off before disconnecting the battery.

Check the head gasket mating surface for warpage using a straightedge and feeler gauge.

Use a spring compressor to compress the springs on the first valve, remove the keepers, then carefully release the compressor and take out the retainer, spring, and spring seat if used.

Using a new head gasket, outline the cylinders and bolt pattern on cardboard, indicating the front of the engine.

The head bolts should be loosened in 1/4-turn increments in a reverse tightening pattern, and they should be stored in the cardboard holder for reinstallation.

Cover any holes in the block with shop rags to keep debris out, and use a shop rag or vacuum cleaner to remove any debris that falls into the cylinders.