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.