Removal of the valve cover begins by removing engine cover and any side covers which may be there then unscrew the spark plug wires attached to spark plugs. When needed, loosen the clip on crankcase breather hose that is connected on the valve cover and place it aside. Disconnect any electrical wiring, ground straps or hoses which connects to the valve cover including the power steering hose retaining tab on the right valve cover of a DOHC engine. Then, loosen the retaining nuts and put off the valve cover on the cylinder head. A stuck cover can get free by tapping the end with a block of wood and a hammer, or with a flexible putty knife, which can be used to cut the seal without destroying the sealing surfaces. To install it, the mating areas of the housing or the cylinder head and cover must be clean and one should use a gasket scraper to remove sealant and the old gasket material then wash it with lacquer thinner or acetone to avoid oil spills. On the DOHC engines, examine the end plug rubber and change where necessary. In case of SOHC engines, use RTV sealant on the corners of the camshaft bearing caps and in case of DOHC engines, apply sealant on the corners of the camshaft front bearing cap and on the camshaft drive chain tensioner. Replace the old valve cover gasket with a new one and place it over the studs on the cylinder head, and, in the case of DOHC engines, the spark plug tube grommet gasket with the index marks faced by the timing belt end. Lastly, fit the valve cover and fit the retaining nuts in a number of steps, and then refit the other parts, start the engine and test whether there is any leakage of oil or not.