GM 14085481 Crankshaft

The following are the general steps to follow, Start by withdrawing the engine of the car and placing on a stable stand. For the L4 engines, remove crankshaft pulley and hub assembly, for V6 engines, remove crankshaft pulley assembly, torsional damper assembly. Subsequently, remove the oil pan, and the oil pump assembly. L4 engines timing gear cover should be removed; L4 V6 engines water pump, crankcase front cover, camshaft sprocket and the timing chain should also be removed. Continue and take out the pistons and the connecting rods from the crankshaft and finally the flywheel. See to it that all the main bearing caps have corresponding positions of the engine block if not you can dent them to help in identification. Remove the main bearing caps, as well as the corresponding bearings that are fixed to the crankshaft, and put all of them on a workbench in the same sequence as they are installed in the engine block. Carefully raise the crankshaft out of the engine block, using care to prevent any scratching of the rod bearing bores, as you would during installation; then extract the rear main oil seal. Last but not the least; remove the main bearings and the main bearing cap from the block maintaining their positions respectively, further depending on the crankshaft configuration; the gear or sprocket might be pulled out using a special tool known as puller.

After removing the engine from the car, it should be mounted on a work stand with the oil pan facing up.

For L4 engines, take off the crankshaft pulley and hub assembly.

Ensure the correct bearings are used.

Measure the connecting rod side clearance with a feeler gauge between the connecting rod caps, and if it falls outside the specified tolerance, replace the rod assembly.

For a Quad-4 engine, check the oil pump drive gear for wear and damage. If replacement is required, take the crankshaft to a dealer service department or an automotive machine shop for removal and installation of the new gear.

If the original bearing inserts are still in place, remove them from the block and caps, and then meticulously clean the bearing surfaces with a lint-free cloth.

If a dial indicator is not available, you can gently pry or push the crankshaft all the way to the front of the engine and slip feeler gauges between the crankshaft and the front face of the thrust main bearing to determine the clearance.

If any are evident, the crankshaft will need professional regrinding.

The crankshaft gear at the front can be removed using a special puller designed for this purpose.

Remove the main bearing cap bolts and lift out the caps, laying them out in order for correct reinstallation.

Install the main bearings in the cylinder block and main bearing caps, lubricating the bearing surfaces with engine oil.

Use a micrometer to test each journal and crankpin at several points for ovality. If the measurement exceeds 0.001 inch, regrinding is necessary.

Measure at various points around the journal's circumference.

Finally, take out the main bearings and main bearing caps from the block, keeping them organized by their positions.

Undersize bearings are available to match the recommended regrind diameter, typically supplied by the dealer with the reconditioned crankshaft.

Tap the end of the crankshaft with a lead hammer to align the rear bearing properly, then retorque all bearing cap bolts to the proper specification.

Tap the end of the crankshaft with a lead hammer to align the rear bearing properly, then retorque all bearing cap bolts to the proper specification.

Before removing the crankshaft, check the endplay by mounting a dial indicator with the stem aligned with the crankshaft and touching one of the crank throws.

If unmarked, use stamping dies or a center punch to label them. Most caps have a cast-in arrow indicating the front direction.

Check the main bearing oil clearance using Plastigage, ensuring it is placed parallel to the journal axis without covering oil holes.

By measuring at various points around the journal's circumference, you can determine if the journal is worn out-of-round, and take measurements at each end of the journal, near the crank throw, to check for taper.