To remove the components, start by draining the engine oil and the cooling system, then take off the air cleaner assembly and the radiator. If applicable, remove the self-levelling suspension system hydraulic pump, which can be moved aside while keeping the hydraulic lines connected. Next, take off the camshaft cover, coolant pump, and auxiliary drivebelt(s). For models with air conditioning, unscrew the securing bolts and remove the compressor drivebelt tensioner strut, then unbolt the compressor mounting bracket and move the compressor aside while ensuring the refrigerant lines remain connected. Turn the engine clockwise to bring No 1 piston to TDC, aligning the crankshaft and camshaft timing marks, then remove the crankshaft pulley/vibration damper and hub, followed by the distributor and TDC sensor if applicable. Disconnect the throttle cable and unbolt the transmission earth strap if necessary, then remove the rear engine mounting and sump. Unscrew the bolts securing the oil pump pick-up tube bracket and withdraw it, then unscrew the bolts securing the cylinder head to the timing chain cover and remove the cover along with the oil pick-up tube, taking care not to damage the cylinder head gasket. If not already done, remove the Woodruff key and slide the spacing ring from the front of the crankshaft. For refitting, check the cylinder head gasket for damage and clean all traces of old gasket or sealant from the mating faces. Renew the crankshaft front oil seal, lubricate the oil supply tube O-ring, and place the new gasket or apply sealant to the mating faces. Cut the gasket at specified points if applicable, then position the timing chain cover over the locating dowels, aligning the oil pump inner rotor if necessary. Refit the timing chain cover bolts finger-tight, then reattach the oil pick-up pipe bracket and tighten the securing nut and bolts. Slide the spacer ring onto the front of the crankshaft and refit the Woodruff key. Refit the air conditioning compressor and its mounting bracket if applicable, then secure the cylinder head to the timing chain cover without fully tightening the bolts. Progressively tighten all front timing chain cover bolts to the specified torque in a diagonal sequence, then reattach the sump, rear engine mounting, and transmission earth strap if applicable. Reconnect and adjust the throttle cable, then refit the TDC sensor, distributor, crankshaft pulley/vibration damper, and auxiliary drivebelt(s). Refit the coolant pump, self-levelling suspension system hydraulic pump if applicable, camshaft cover, radiator, and air cleaner, then reconnect the battery negative lead. Finally, refill the cooling system and engine with oil.