Crankshaft — check (Opel Astra G)

Checking axial play

1. The axial clearance of the crankshaft is checked before removal from the engine, when the crankshaft can rotate freely in the main bearings.

2. Axial clearance is checked using a dial indicator. Move the crankshaft to the stop to the side and set the dial indicator scale to zero. Move the crankshaft to the opposite side and read the dial indicator reading (see photo). Compare the result with the standard. If the clearance exceeds the standard, then the thrust half rings will need to be replaced.



3. If there is no indicator, the axial play can be checked with a feeler gauge. Move the crankshaft as far as it will go toward the flywheel, then measure the play by inserting feeler gauges into the gap between the crankshaft cheek and the thrust half ring next to the 3rd main bearing

Checking the status

4. Wash the crankshaft with solvent and dry. Thoroughly clean the oil passages inside the crankshaft.

5. Check the connecting rod necks for signs of uneven wear, cracks, scuff marks and pitting (pits).

6. Wear of the connecting rod journal is accompanied by a distinct metallic knock when the engine is running (it is especially noticeable when you press the throttle pedal while driving at low speeds) and a noticeable drop in oil pressure.

Wear of the main bearings is accompanied by strong engine vibration and a dull rumbling sound that increases with increasing engine speed, as well as a noticeable drop in oil pressure.

7. Check the roughness of the crankshaft journals by running your finger over them. Any roughness (which appears simultaneously with obvious signs of wear of the main and connecting rod bearings) indicates the need for regrinding of the crankshaft journals or its replacement

8. Check the crankshaft runout in the central part by installing the crankshaft in prismatic supports. If the runout exceeds the norm, the crankshaft must be replaced.

9. If the crankshaft journals have been reground, remove burrs around the lubrication holes.

10. Measure the diameter of the main and connecting rod journals (see photo). Determine the ovality of the necks by measuring the diameter at several points around the neck. Check the taper by measuring the diameter near the opposite cheeks of the necks. Compare the results with the standard ones.



11. Check the condition of the crankshaft sealing journals. If a deep groove has formed on these journals in place of the working edges of the seal, consult a specialist, as either repair or replacement of the crankshaft will be required.

12. Main and connecting rod bearings of two repair sizes are supplied as spare parts (with a diameter reduction of 0.25 and 0.5 mm). If the crankshaft has not been repaired, the journals should be reground and the liners should be replaced with repair ones.