GM 12588616 Engine Crankshaft

They cannot be removed with the engine still installed in the car, more so, in order to remove the crankshaft, other parts like the driveplate, crankshaft pulley, timing chain, oil pan, oil pump body, oil filter as well as the pistons/connecting rods are also usually removed. Bearing in mind that it is necessary to remove the main bearing caps, then, at this stage, get a dial indicator and place it facing the crankshaft's endplay. Stack the crankshaft to the rear, rotate the indicator plunger until the readings zeros, and then stack the crankshaft to the front where again you should get the new reading which varies from 0.003 to 0.010 inch (0.076 to 0.254 mm). In case of lack of the dial indicator, the feeler gauges can be used for measuring the clearance. V8 - Fit a slidehammer with the spreading end against the flats of the main bearing cap bolts and try and remove the caps wee bit at a time Remove main bearing cap bolts and caps. Take time to lift the crankshaft out together with its bearing inserts still in position, and then replace the main bearing caps on their rightful position. For installation, be sure that the engine block and the crankshaft are clean and checked. Place the engine block on its head, take off the main bearing caps, and make a thorough cleaning of to bearing interfaces. New inserts should be fitted to the upper main bearing so that the oil holes run longitudinally and the lower inserts positioned in the caps. Look through the oil through Plastigage in order to make sure that no dirt and oil may affect the measurement. In case clearance is wrong, correct sizes of the bearing must be checked and, if needed, be changed. Once Plastigage build-up has been removed, lightly coat the bearing surfaces with grease or assembly lube before reemploying the crankshaft. Having done that, clean the faces of the bearing inserts and apply lubricant, the caps are then fitted and the bolts are tightened in the correct sequence. Check the crankshaft end play again and go for run-in torque of not more than 50 in-lbs for the crank to rotate freely. Last of all, acquire a new and better rear main oil seal.

For installation, ensure the engine block and crankshaft are clean and inspected. Position the engine block upside down, remove the main bearing caps, and clean the bearing surfaces.