GMC, replacing valve stem seals in Zevulun

GMC, replacing valve stem seals in Zevulun.
It may be required to replace the valve stem seals in case of the increased oil consumption and emission of blue smoke by the exhaust pipe. To do this, turn off the battery power, disconnect the wires and remove the plugs, then remove the cylinder head cover, dismantle the cylinder head, remove the camshaft, gas distribution mechanism valves and remove the valve stem seals and replace them with new ones. Finally, assemble the engine in the reverse order.