Before the removal of the components, loose fuel system pressure should be released, the cable connecting the negative terminal of the battery should be detached and the cooling system drained. Second, take off the upper intake manifold and spacer, the catalytic converter assemblies, timing belt and camshaft sprockets. Remove the coolant passage from the cylinder heads: undo the mounting bolts and using a soft-faced hammer strike the passage gently. Before an advanced technique has to be employed, physically get rid off the valve cover and the rocker arms/shafts assembly, fuel rails and injectors and the lower intake manifold(s). Taper the cylinder head bolts by turning them in the reverse order that they were tightened and if they can't be removed, then use hand strength to take out the cylinder head which should be lifted off the engine block, though some groundwork may be needed as it is usually rather stuck. For installation, it is advisable that the mating surfaces of the cylinder heads and block should be clean, using the gasket scraper and cleaning agents, while on the same note it should not mar the aluminum. Check the surface for tiny pits or forker marks, repair them with a file as for deep ones use machining. Using a tap chase the threads into the head bolt holes and clean the holes with compressed air. Carry out some cleaning processes to the bolts and change those that do not meet the minimum prescribed diameter, preferably go for new head bolts. The oil-control orifices need to be washed clean and be reassembled with new O-rings; proper positioning of gaskets. Place the head back on the block so as not to harm the gasket, coat the bolt threads and under the head bolts with clean engine oil and then put them back in the right sequence and tighten. The rest of the steps are in the reverse order going by the process of elimination. Lastly, the battery should be connected, the cooling system topped up, oil and filter replaced, engine crank for 10 minutes and check for leakage, crank at low speed for five minutes to free air in lost motion assemblies and some tapping noise may be heard from tappets which, if continues then that itself is a sign of a problem.