Pulley Runout Causing Accessory Drive Belt Squeal. Chevrolet Lumina Export 2007

Subject:

Pulley Runout Causing Accessory Drive Belt Squeal

Models:

2007 Chevrolet Caprice, Lumina (Export)

with V6 LE0 Engine

Built Prior to VIN Breakpoint 7L866958

Vehicles may exhibit an accessory drive belt squeal noise that may be present when the vehicle is cold and generally within the first few minutes of operation until engine is warmed up.

Investigations of accessory drive belt squeal on early build vehicles have defined that power steering pump pulley lateral runout may be out of specification.

Important: Before removing the belt, take a note of direction of the belt. Mark the belt with an arrow mark towards the front of vehicle and place it back in the same direction when the procedure is completed.

Confirm that the accessory drive belt noise is coming from the LH side of the engine compartment.


(1)	Check rib runout in this area

Remove the accessory drive belt and spin the P/S pulley and measure the lateral runout. Allowable runout on the belt ribs of the power steering pulley is 0 to 0.4 mm. Do NOT check the runout via the outer flanges as these flanges are not as accurate as the inner belt ribs. Use of a dial indicator is recommended for this check to ensure accuracy. If outside of specification, replace the P/S pump pulley.

Reinstall the original drive belt. Install as per marking as noted at start of this procedure. Test to confirm that the noise is eliminated.

Additional Checks

Should any noise persist after a pulley replacement, the following checks should be performed:

•	Check the P/S pulley (1) to P/S pump shaft (2) offset. If not to specification, align the pulley back to specification (0 to 0.3 mm underflush).

•	Check the belt alignment to ensure that misalignment of the belt or pulleys is not the cause.