A/C FLUTTER NOISE AT HIGH- BLOWER- ALLANTE (REPAIR)

A/C FLUTTER NOISE AT HIGH BLOWER SPEED

VEHICLES AFFECTED: 1987 ALLANTE

Some 1987 Allantes built prior to VIN 102526 may exhibit a fluttering noise from the A/C ducts at high blower speed. This noise is caused by the rubber seal of the up-down valve (door) vibrating against its lower seat. To repair this condition, use the following procedure:

1. Start car and set the up-down lever to the "down" position. This will command the up-down valve (door) to its "up" position, sealing off air to the A/C ducts.

2. Turn the ignition to the "off" position.

3. Remove the passenger side hush panel.

4. Inspect A/C module. Some vehicles may have no retainer, a retainer installed upside down, or a retainer installed in the wrong location. See Figure 1 for correct location.

5. Drill a 7/32" hole in the module as indicated in Figure 1. If the vehicle has an incorrectly installed retainer preventing drilling of the 7/32" hole in the prescribed location, move forward or rearward maintaining a distance of 30mm from the A/C module contour.

6. Trim the head of the retainer, P/N 411700, as indicated in Figure 2 to allow a correct fit along the edge of the heater duct.

7. Install retainer by pressing upward into HVAC module.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.