GMC, valve cover gasket replacement in Zevulun

GMC, valve cover gasket replacement in Zevulun.
The valve cover gasket should be replaced in the following cases: appearance of engine oil traces on the side walls of the cylinder head; assembling the engine after overhaul; detection of any gasket defects during repair. To replace the valve cover, disconnect the battery, remove the wire ends from the plugs, remove the valve cover attachments, remove the cover fasteners, remove the worn seal from the pockets, clean the working surface, apply a sealant and install a new gasket into the grooves.