The crankshaft is loose and can only be removed after removing the engine from the car, provided other parts which include the flywheel, crankshaft pulley, timing chain, oil pan, oil pump body, oil filter,
Piston/connecting rod assembly have been removed. Prior to the removal, use a dial to set a dial indicator parallel to the crankshaft in order to measure the crankshaft endplay. Move the crankshaft to the rear of the cylinder and note down the reading on the indicator; move the crankshaft to the front and take another reading; the amount of movement should range from 0.003 to 0.010 inch (0.076 to 0.254 mm). If you do not have access to dial indicator, then clearance can be measured by the use of feeler gauges. Loosen the main bearing cap bolts progressively, after that, take off the main bearing caps paying attention not to drop the bearing inserts. It is very heavy; better to lift it out gingerly or better still with some help because of the weight. It is recommended for installation that the engine block and crankshaft should be cleaned and checked. Place the engine block on its head, remove any crossbars or caps from the above and scrub the bearing area. New upper main bearing inserts are to be installed without being confused with each other and are required to be clean. Examine the oil holes on the crankshaft; thereafter, position the crankshaft into its proper place. When the bearing is not fitted permanently, inspect the clearance of the main bearing by using Plastigage and it should be slightly smaller than the width of the journal. Position only the Plastigage on each journal and then fit the caps without moving the Plastigage then torque the bolts on turn wise manner. You should then read the width of the crushed Plastigage against the scale in order to get the clearance. If the clearance is incorrect there may be dirt or oil interference and if so there may be a range of different bearing inserts to consider. Remove any Plastigage left on the journals and insert faces and lubricate bearing surface and thrust faces with a thin film of grease or assembly lube. Place the crankshaft back onto the engine clean the concluded faces of the bearing insert, and install the main bearing caps properly. Coat a thread of the bolt with the clean engine oil, tighten the bolt loosely and then tighten them strictly following the right pattern. Again check the crankshaft end play and turn the crankshaft making sure it moves freely and with a running torque of 50 in lbs or less. Last but not the least install a new rear main oil seal.