GM Service Manual Online
For 1990-2009 cars only
  1. Check all the mounting for proper torque (bolt and/or nut). A loose mounting causes noise.
  2. Jounce the vehicle to isolate the suspected unit if all the mountings are intact.
  3. Quickly push down (jouncing) and then lift up on the corner of the bumper that is nearest to the strut cartridge being checked to test each strut cartridge.
  4. If practical, ride with the owner to be sure that you understand the complaint, before proceeding to the next step.
  5. Stroke the strut damper to detect other objectionable noises.
  6. Any sound other than hissing is abnormal.
  7. Replace the strut if an abnormal sound occurs. Refer to Strut, Strut Component, and Spring Replacement in Front Suspension.
  8. Adjust the alignment as necessary.