A few 1996 and all 1997 and later 4.3L V6 and 5.0L, 5.7L V8 engines have a non-reusable plastic front cover that has to be replaced because it is part of the oil pan gasket set and its re-use will lead to oil leaks while 1998 and later 7.4L V8 engines have a front cover and gasket which should Letting start by removing the negative battery terminal and then draining out the cooling system. Take off the upper and lower fan shrouds, drive belt, cooling fan and water pump or coolant manifold. Slightly turn crankshaft 360 degrees more so that No.1 piston is positioned at TDC of the compression stroke though do not turn the crankshaft until the timing chain and sprockets are replaced. The crankshaft pulley, the vibration damper, the crankshaft position sensor and the nut of the wiring harness fastened to the front cover must be disconnected. Take out the oil pan and cover bolts to unbolt the timing chain cover from the block, thus, maybe breaking the gasket seal. For 4.3L V6 and 5.0L, 5.7L V8 engines, the timing chain cover is of composite type and is non-reusable, it is suggested to renew the oil seal simultaneously. Take off the crankshaft position sensor reluctor ring and measure how much timing chain is loose like freeplay, If it reaches or goes past five and eight of an inch, then replace the chain and both sprockets. Remove the camshaft sprocket and chain assembly with the aerospace balance shaft drive gear still fitted to the camshaft. Scrub the contact and mating surfaces of the engine block and if the vehicle is being fitted with a new timing chain, align the key way of the crankshaft sprocket to the Woodruff keyway. N.B. Ensure that the sprocket is fitted to the crank and bolted firmly, do not hammer the sprocket since it may distort. For 4.3L V6 engines, set the balance shaft gears before the timing chain and the camshaft sprocket, that the timing indicators are correctly oriented. Put a non hardening thread locking compound on the sprocket bolt thread and the chain should be lubricated with some fresh engine oil. Crankshaft position sensor reluctor ring, with its dished side outwards, return the crankshaft and apply some RTV sealant on the sealing surface of the engine block and fit new front cover and oil seal assembly. Tighten to 20 Yamaki lb/ft the cover retaining bolts then bolt on the oil pan, vibration damper for crank shaft position sensor with new O-ring. For 2018 and later models, the items are vibration damper, vacuum pump, air conditioning compressor, oil pan, and oil pump. Turn the number one piston into Top Dead Center, pull out the electrical connectors connected to the Camshaft Position Sensor and the Actuator Magnet, and unscrew the cover bolts so as to detach the Timing Chain Cover from the Block. Check the position of the timing marks before unbolting the solenoid valve and the actuator. Check the timing chain tensioner and sprockets for any sign of wear and if the sprocket is worn or has to be replaced, the sprocket must be taken of the crankshaft discreetly. At installation, always purchase the timing chains with the sprockets and clean all of the sealing surfaces; then apply RTV sealant to the timing cover. The timing chain cover is then to be fitted loosely, the bolts are to be tightly fixed in a sequence and a new crankshaft oil seal is to be fitted. But to complete the installation the cooling system should be refilled and the engine oil topped up, the engine oil filter replaced and when the engine is running, check for signs of leakage.
Posted by GMPartsGiant Specialist