1. Clean the crankshaft using an appropriate solvent and dry it with compressed air.
2. Check the crankshaft main and connecting rod journals for wear, corrosion and cracks.
3. Wear of the connecting rod journal is characterized by metallic knocks during engine operation, especially under load, at low speeds and a decrease in oil pressure.
4. The wear of the crankshaft main journals is characterized by strong engine vibration and metallic knock, which increases with increasing engine speed, as well as a decrease in oil pressure.
5. Check the crankshaft journals for roughness. Any noticeable roughness indicates that the crankshaft needs to be reground or replaced.
6. If the crankshaft has been reground, check for burrs around the grease holes. If there are burrs, remove them with a fine file or scraper and carefully clean the holes and channels from chips.
7. Using a micrometer, measure the diameter of the crankshaft journals and crankpins and compare the results with specifications. Measure the necks at several points both in diameter and along the length of the neck, which will reveal ovality and taper, if present.
8. Check the oil seal contact surfaces at each end of the crankshaft for wear or other damage. If the wear of the neck from the seal is large, then the crankshaft may need to be replaced.