Correction
The corrective procedure below has been developed for the 4.0L and 4.6L engines identified above, and can be used to service all model years of 4.0L and 4.6L engines exhibiting these noises. If a vehicle is encountered with any of the above concerns and the condition is still present after completing all of the diagnostic procedures listed in the Service Manual, then perform the following procedure:1. Check power steering fluid level and add fluid if necessary.
2. Start vehicle and run for 3 minutes, idling in Park with the hood open.
3. While the engine is running, verify the type and location of the noise described by the customer. It may be necessary to increase the engine speed up to approximately 2,500 rpm and closely listen for noise.
4. Remove the accessory drive belt. It is important to note the belt direction of travel by marking an arrow on the belt, since this belt will be re-installed in Step 14 of this procedure.
5. Inspect the belt grooves for damage and pilling (Figure 1). Pilling appears as shiny areas in the grooves of the accessory drive belt. Completely describe any belt damage or pilling observed on the Repair Order.
6. Start the vehicle and listen for noise. If the noise is still present, the source is not the belt or accessory drive components, follow the Engine Mechanical Noise Diagnosis Section of the applicable Service Manual. If the noise is no longer present, proceed to the next step of this procedure.
7. Inspect the accessory drive pulleys for damage such as chips, dings, dents, or uncommon wear patterns. Check all pulleys for trueness or unusual wear. To determine trueness, rotate the pulley and compare the vertical surface to a fixed point using a measuring device. If the measured distance between the two points remains constant, the pulley is running true, if the distance varies, the pulley is not running true. Replace any accessory drive pulleys which are not true, damaged or worn.
8. Remove the power steering pump and bracket and place in a shop vise (Figure 2). Inspect the power steering pulley for cracks, chips and excessive runout. Replace any damaged pulleys.
9. Remove any flash from the mold parting lines in the belt contact area of the power steering pump pulley (Figure 3). Flash can be detected by running your finger nail perpendicular to the grooves in the pulley. Use a piece of 400 grit sandpaper folded into a "V" or a small smooth file to remove all flash from the entire belt contact area of the power steering pump pulley. Continue to sand the pulley until the flash can no longer be detected in the entire belt contact area by running your finger nail perpendicular to the grooves in the pulley. Thoroughly clean the pulley with shop air and a clean shop towel after removing the flash.
10. Remove the dust cap and check the power steering pump pulley to shaft flushness with a straight edge (Figure 4). If necessary, adjust the pulley so it is flush with the power steering pump shaft using pulley installer tool J 25033-C, and remover tool J 38825.
11. File a chamfer on the front face of engine block where the power steering pump mounting bracket locating pad is located so that the sharp corner has been eliminated (Figure 5). Do not file the power steering pump mounting bracket.
12.
a. For Cadillac vehicles:
Inspect the idler pulley assembly for cross threading. If there is evidence of cross threading, repair idler pulley assembly as required. Assure that the idler pulley bolt is tight (Figure 7). The proper torque for the bolt is 50 N.m (37 lb ft). This step will help eliminate squeaking noises which occur during the first minute of running after a cold start and then go away.
b. For Oldsmobile Aurora vehicles:
Remove the front engine mount and mount plate. See the 1997 Oldsmobile Aurora service manual for proper procedure. Inspect the idler pulley assembly for cross threading. If there is evidence of cross threading, repair idler pulley assembly as required. Assure that the idler pulley stud is tight (Figure 8). The proper torque for the stud is 50 N.m (37 lb ft). This step will help eliminate squeaking noises which occur during the first minute of running after a cold start and then go away.
13. Reinstall the power steering pump and bracket assembly, making sure to push and hold the pump toward the rear of the engine while tightening the attaching bolt. (The proper torque for the bolt is 50 N.m (37 lb ft). Verify that there is no gap between the power steering pump bracket locating ear and the engine block (Figure 6). Add power steering fluid as necessary to fill the power steering system.
14. Install accessory drive belt removed in Step Number 4, observing the direction of travel arrow placed on the belt when it was removed. Start the engine and verify that all components removed have been reassembled properly.
15. Allow the vehicle to soak outside overnight.
16. Check power steering fluid level, and add fluid if necessary.
17. Start vehicle and run for three minutes, idling in Park with the hood open.
18. Re-evaluate for noise. It may be necessary to increase the engine speed up to approximately 2,500 RPM and listen closely to the A/C-generator area for a squeaking noise. If the noise has been eliminated, shut off the engine, and remove the accessory drive belt. Tag the removed belt with all pertinent part return information and return it to the warranty parts center, then proceed to step number 20. If the noise is still present, proceed to the next step.
19. Loosen the two rear generator bracket to block bolts (Figure 9 - Number 1). Remove the lower front generator mounting bolt (Figure 9 - Number 2). Install one P/N 00187372 shim washer (20 mm outside diameter, 10 mm hole diameter, 1.8 mm thick) between the lower front generator mounting boss and the lower front generator mounting bracket. Install and tighten the lower front generator mounting bolt. (The proper torque for the bolt is 47 N.m (35 lb ft) Tighten the two rear generator bracket to block bolts. (The proper torque for the bolts is 47 N.m (35 lb ft.)
20. Install a new accessory drive belt P/N 12561088.
21. Return vehicle to customer.