Bulletin No.: PI1286A
Date: Oct-2015

Subject:

Hood Flutter, Shake or Vibration at Highway Speeds or over Rough Road Conditions

Models:

2015-2016 Cadillac Escalade, Escalade ESV
2014 Chevrolet Silverado 1500
2015-2016 Chevrolet Silverado, Suburban, Tahoe
2014 GMC Sierra 1500
2015-2016 GMC Sierra, Yukon, Yukon XL

Attention:

This PI also applies to any of the above models that may be Export vehicles.

This PI has been revised to add the 2016 Model Year. Please discard PI1286.

Condition/Concern
Some customers may comment on the vehicle hood fluttering, vibrating or displaying visible motion at highway speeds or over rough road surfaces.
The inner and outer hood panels may not be sufficiently bonded together at all points. At highway speeds or over rough surfaces, the sheet metal may be able to
flutter at some locations.

1.

Separation

2.

Gap/Void

Recommendation/Instructions
Apply panel vibration control material between the inner and outer panels. The procedure below outlines the proper repair instructions. The accompanying
illustrations show the most likely areas that may be the source of the fluttering.
Important: The hood fluttering or vibration DOES NOT indicate that any adjustment of the hood latch, striker or bumpers is needed. Hood overslam bumpers

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that are not in contact or a hood latch that is set slightly high may also lead to hood vibration. However, this procedure is for hood inner to outer adhesive
separation after the latch position and overslam bumper contact have been verified.
1.

Open the hood.

2.

Remove the 6 plastic fasteners retaining the underhood insulation pad using a trim tool.

3.

Remove the underhood insulation pad.

4.

Cover the engine and the cowl area with a blanket, towel or other protective covering. Panel vibration control material may drip while being applied.

5.

Refer to the picture above (GMC Yukon shown – others similar). In all cases you will be filling the void between the inner and the outer panels to prevent
the metal fluttering. The arrows indicate the areas most likely to require additional bonding. Examine the underhood panel for signs of original factory
shrinkage or insufficient application, similar to the pictures listed in the Condition/Concern section.

6.

Using a non-expanding two-part panel control vibration material, such as SEM 39977* or equivalent, fill the voids between the inner and outer hood
panels as shown in the illustration (one side only indicated). Keep the tip of the applicator right up against the panel in order to allow the material to flow in
between the panels. Follow the manufacturers instructions for proper application.
Important: While most of the areas to bond will be covered by the underhood insulation pad, maintain a neat appearance.

7.

Reinstall the underhood insulation pad.

8.

Install the 6 retainers.

9.

Remove the blanket covering the engine and fenders.

10. Inspect for and clean up any dripped material.
11. Close the hood.
*We believe these sources and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse,
indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources

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Parts Information
For product ordering information, call SEM at 1-866-327-7829. SEM products are also available at local automotive paint supply stores.
Part Number

Description

Material Allowance

SEM 39977*

Panel Control Vibration Material

$20.00
$35.00 CDN

*There is enough material to do approximately 2 vehicles. Store the remaining material for future use.

Warranty Information
For vehicles repaired under warranty, use:
Labor Operation

Description

Labor Time

1480308*

Bond Inner and Outer Hood Panels

0.4 hr

*This is a unique Labor Operation for Bulletin use only. It will not be published in the Labor Time Guide.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

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