Pinpoint Test F: Drumming Noise

F1 CHECK THE EXHAUST SYSTEM
- Key in START position.
- Increase the engine RPM until the noise is the loudest. Note the engine RPM.
- Key in OFF position.
- Add approximately 9 kg (20 lb) of weight to the exhaust system. First place the weight at the tail pipe and test, then at the front exhaust pipe.
  
  Fig 1: Identifying Tail Pipe And Front Exhaust Pipe
  Courtesy of FORD MOTOR CO.
- Key in START position.
- Increase the engine RPM and listen for the drumming noise. Note the engine RPM if the noise occurs.
- Key in OFF position.
- Using a vibration analyzer (VA), determine the amount of vibration that occurs with the drumming poise.
- Is the noise/vibration reduced or eliminated, or does the noise/vibration occur at a different RPM?
Yes : CARRY OUT EXHAUST SYSTEM NEUTRALIZING in this article. TEST the system for normal operation.

No : GO to F2.
F2 POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING
- Carry out POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING in this article. Test the system for normal operation.
- Is the noise reduced or eliminated?
Yes : Vehicle OK. TEST the system for normal operation.

No : CONDUCT diagnosis of other suspect components.