Before performing a component swap, it is necessary to discharge the cooling system and crankcase; fully remove the oil pan and the
Radiator; collect the coolant in a sealable vessel so that pets will not be harmed. Next, remove on cylinder front cover, water pump, drive belt and camshaft timing gear. Depending on the model, employ the services of a clutch aligner to have the crankshaft sprocket pulled off. As for the installation, you need to place the keyway in the gear and than slide it onto the shaft and fit the timing chain around the crankshaft sprocket and camshaft sprocket when all the timing marks should coincide. Satisfy yourself there is the appropriate camshaft end play and replace the thrust plate if required. Rotating the crankshaft until both the key and timing marks are in their correct positions, fit gear into the crankshaft with a special tool. Reconnect the cylinder front cover, oil pan and the radiator, add coolants to the engine and but air into it, switch on the engine and set the ignition timing and look for any signs of leakage. For example for timing chain deflection, first, then release the tensioner, turn the crankshaft to eat up the chain travel, put a scribe mark, and then again measure the deflection. If still higher replace the timing chain and sprockets and if the wear of the tensioner is beyond 1.5mm, replace it. During the installation of the crankshaft sprocket, one should use the thread lock and sealer to fill the keyway chamfer cavity. For 4.0L engine to 2006: Detach the front cover and radiator, turn the engine to TDC of the compression stroke at No. 1 cylinder, peel off the camshaft sprocket bolt, the sprocket retaining key and also the sprockets and the timing chains. If necessary, then unbolt the tensioner and the guide, then bolt the timing chain guide in the right position and make sure that the bolts are tightened. Check which timing mark coincides with the other on the sprockets, fit the sprockets and chain as well as tighten the camshaft sprocket bolt. The tensioner with the clip should be fitted and the alignment of the sprockets and their relative position to the chain should be tested before the camshaft sprocket bolt is tightened. Last but not the least, provide the tensioner clip, measure camshaft end-play, and then put front cover alongwith the bolts.