ALL UTILITY VEHICLES WITH ROOF RACK (RPO V54 & V55)

SUBJECT: ROOF RACK HOWL/WINDNOISE (INSTALL RUBBER CROSS RAIL CAP)

VEHICLES AFFECTED: ALL S/T UTILITY VEHICLES W/ROOF RACK (RPO V54 AND V55)

Some S/T vehicles with option (RPO V54 and V55) roof racks may experience a roof rack howl. This howl has been determined to be caused by the height difference between the roof rack cross rails and the rubber strip within the rail. This condition results in a howl/windnoise as air flows across the rail, much like a reed in a wind instrument.

To eliminate this condition a new rubber cross rail cap (part #15659287) should be installed. This new cap will repair the condition because it closer to the cross rail. Refer to Figure 1 for the view of cross rail with installed rubber cap.

SERVICE PROCEDURE

1. Check cross rails for proper installation.

2. Remove and install cross rail, wide side forward (if required).

3. Mark old rubber cap to distinguish from new part (the new part is the same as the old part, except for an increased width which is not detectable.

4. Remove old rubber cap.

5. Lube the cross rail cap with mild soap and water or equivalent.

6. Slide in new rubber cap, wide side forward. (Cross rail does not need to be removed as the new part can be worked into place by hand.)

7. Test vehicle for howl condition.

In most cases only the front cross rail cap will be needed to eliminate the howl condition. However, if appropriate, this procedure may be applied to the rear cross rail cap as well.

NOTE: Install cross rail and cross rail cap with wide side forward as shown in Fig. 1. Do not cut cross rail cap to fit, work into cross rail until all slack has been removed.

Part Number Description Quantity ----------- --------------------- --------------- 15659287 rubber cross rail cap 1 per rail (as needed)

Use the most applicable Labour Operation and Time from the Canadian Labour Time Guide.

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.