The tires and wheels on your vehicle were aligned and balanced carefully at the factory to give you the longest tire life and best overall performance. Adjustments to wheel alignment and tire balancing will not be necessary on a regular basis. However, if you notice unusual tire wear or your vehicle pulling to one side or the other, the alignment might need to be checked.
If you notice your vehicle vibrating when driving on a smooth road, the tires and wheels might need to be rebalanced. See your dealer/retailer for proper diagnosis.
Chevrolet Cobalt Service & Repair Manual. Crankshaft Main Bearing Clearance Measure
Method A
1.
Measure the crankshaft bearing journal
diameter with a micrometer in several places, 90 degrees apart.
Average the measurements.
2.
Measure the crankshaft bearing journal
taper and runout.
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