Start by blowing the cooling system and removing spark plugs, depressurize the fuel system and remove the battery negative lead. Next, take out the inlet manifold, fuel pump and camshaft position sensor housing from the cylinder head to camshaft sprockets. Disconnect the crankcase breather hose from the back of the camshaft cover, and remove the camshaft cover(s), taking care to make a note of the position of the bolts, since at least one holds a wiring plug bracket. Lift off the cover(s) and recover the gasket(s). Remove the two retaining plates at the timing belt end of the head, which hold the timing belt upper cover and add support to the cylinder head upper part. Unscrew the thirty-two bolts that hold the upper section in place in order to prevent distortion, and record their sizes and designs. In the case where a stud is fitted, unscrew it after removing the upper section by tightening two nuts against each other. Carefully remove the upper section of the cylinder head and save the rubber gasket to replace it when reassembling the cylinder head. Mark the positions of the camshaft sprocket locating pegs for correct refitting; then the camshafts with the oil seals can be lifted out, taking care of the lobes. Remove the oil seals and get new ones to be able to reassemble. Prepare a suitable receptacle for storage of the hydraulic tappets and rockers, marking them for identification. Remove each rocker and tappet, holding them upright in the container, and endow them in clean engine oil. If needed, fully dismantle the cylinder head and the valve components. Inspect the cam lobes and bearing journals for wearing, and rockers and tappets for damage, with the tappet diameter being measured. Clean the sealant from the mating surfaces of the upper and lower cylinder head sections with a suitable dissolving agent and a soft putty knife so that cleanliness is maintained. Clean off any oil, dirt, or grease from both sections of the cylinder head and dry them off with a lint-free cloth so that all of the oilways are clean. To avoid contact between the piston and the valve, rotate the crankshaft sprocket about 1/4-turn in the anti-clockwise direction. To refit a car, start by oiling the bores of your tappets and your camshaft bearings with good engine oil and then you can insert your tappets and pop the rockers on the original valves. Lubricate the camshafts and position them making sure the sprocket locating pegs are set as noted before removal. Make sure that the mating faces of both the cylinder head sections are cleaned and free from oil or grease and then apply a continuous bead of 3 mm in thickness of Volvo sealant in the grooves of the lower section and some amount of sealant in the upper section. In the center, fit the upper section of the cylinder head and tighten it down before the sealant solidifies. Tighten bolts in turn to specified torque taking note of different torque for two bolt sizes and refit retaining plates at timing belt end and tighten bolts to specified torque. Refit the camshaft cover(s) with a new gasket, tightening the bolts from the middle outwards, reconnect the crankcase breather hose and wiring plug bracket. Fit new camshaft oil seals and then reassemble the inlet manifold, fuel pump and camshaft position sensor housing. Finally, refit the spark plugs and refrigerant in the cooling system.