EI08118 - Power Steering Whine/Growl Noise (Engineering Information)

This bulletin is being revised to change engineering contact information and add the 2009 model year. Please discard Corporate Bulletin Number 08-02-32-004 (Section 02- Steering)

Some customers may comment on a whine or growl noise coming from the power steering.

GM Engineering is attempting to determine the root cause of concerns related to power steering noise. GM has a need to obtain technical information from the technician PRIOR to repair. As a result, this information will be used by engineering to help root-cause the customer's concern and develop/validate a field fix.

Document the following information on the repair order:

1. Verify the VIN and mileage are recorded correctly on the repair order.
2. Which engine is the vehicle equipped with?
3. Document if the customer concern can be duplicated and under what conditions.
4. Fill (if necessary) and bleed the power steering system using the following procedure:

Important: If the dealership does not have a J 23738A (MityVac) or equivalent, bleed the power steering system using the procedure found in SI. Be sure to note on the repair order which procedure was used to bleed the power steering system.

Power Steering System Bleed Procedure Using J 42485 (MityVac) (or equivalent)

Important: Maintain the fluid level throughout the bleed procedure.

4.1.	Fill the fluid reservoir to the FULL COLD level. Leave the cap off.

4.2.	Raise the front wheel off the ground.





4.3.	Attach the J 43485 (Adapter) to the J 23738 (Mityvac), or equivalent. Place the J 43485 on/in the pump reservoir filler neck (refer to graphic). Apply a vacuum of 20 in Hg MAXIMUM.

Note: If the J 43485 (adapter) is not available, an equivalent can be made using a rubber seal/stopper and brass fitting.

Important: An assistant is needed for the next step.

4.4.	Apply vacuum while turning the steering wheel lock to lock. Maintain 20 in Hg while turning. Using a clear line will allow you to see bubbles evacuating system. Stop when no more bubbles are seen.

4.5.	Wait five minutes. Typically vacuum drop is 2-3 in Hg. Verify the fluid level. If the fluid level is low, fill to the full line.

4.6.	Reinstall the cap. Start and idle the engine.

4.7.	Turn the engine off. Verify the fluid level. If the fluid level drops, add fluid. Repeat Steps 4 and 5 until the fluid level stabilizes.

4.8.	Start and idle the engine. Turn the steering wheel 180°-180° in both directions five times. DO NOT TURN TO LOCK.

4.9.	Switch the ignition off. Verify the fluid level.

4.10.

Install the cap. The bleed procedure is complete.

5. Did bleeding the power steering system correct the customer's concern?

•	Yes -- no further repairs are required. Submit a Field Product Report (refer to Corporate Bulletin Number 02-00-89-002F) containing the information noted on the repair order.

•	No -- contact Chris Anderson at 586-947-4313.

For vehicles repaired under warranty, use: