For 1990-2009 cars

1. Check all mountings for proper torque. A loose mounting will cause noise.
2. If all mountings are intact, bounce the vehicle to isolate the suspected unit.

Test each strut assembly in turn by quickly pushing down, then lifting up the corner of the bumper nearest the strut assembly being checked. Use the same amount of effort on each test and note the resistance on compression and rebound. Compare this with a similar having acceptable ride quality. Both strut assemblies should provide the same feeling of resistance.

3. Ride in the vehicle with the owner in order to be sure that you understand the complaint.