Technical Service Bulletins

Checking Crank Pulley Runout

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Checking Crank Pulley Runout

Owners of 2012 Chevy Caprice vehicles (civilian or police) may complain about a belt squeal noise and/or a perceived crankshaft balancer wobble. In most cases, the wobble is an optical illusion because the design of the balancer gives the appearance that it is moving laterally more than it is.

If the concern is experienced, follow theses steps:

1. Push the crankshaft all the way to the rear of the engine.

2. Using a dial indicator with a magnetic base, attach the indicator so that the indicator plunger contacts the rear of the drive belt groove. Note that an inaccurate reading may be obtained if measuring the face of the balancer instead of the rear of the drive belt groove.

3. Rotate the crankshaft manually 360 degrees and note the total amount of balancer runout. If the balancer runout is 0.0157 inch or less, do not replace the balancer. If runout is greater than 0.0157 inch, replace the balancer and perform Step 3 again to verify.

4. If the customer complained of a belt squeal, replace the drive belt.

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