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#PIT5318B: Wind Buffeting Drone Type Noise And/Or Body Pressure Booming And/Or Water Leak - (Jul 30, 2015)
Subject: Wind Buffeting Drone Type Noise And/Or Body Pressure Booming And/Or Water Leak
Models: 2015 Cadillac Escalade Models
2015 Chevrolet Suburban, Tahoe
2015 GMC Yukon Models
This PI was superseded to update Recommendation/Instructions. Please discard PIT5318A.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
Note: In some cases, correcting the roof bows may not eliminate the body pressure booming issue due to the fact that the roof is being excited by some other input(s). These other areas will need to be addressed if the body pressure booming is still present at the completion of this PI. Examples of inputs that can excite the roof may be:
Tires with excessive road force (Reference "condition 1" in the latest version of PI1354)
Exhaust back pressure valve issues (Reference the latest version of PIT5404)
Rear axle related issues such as pitchline runout (Reference "Other Sources of Vibrations" Step 3 in the latest version of PI1354)
Some owners may comment of a wind buffeting/droan noise or body/pressure booming (the feeling of pressure in the ears) while driving. The body booming issue may be more noticeable when the engine is in V4 mode for active fuel management (AFM). In some cases, they may also notice a water leak from the headliner area, if equipped with a sunroof.
These concerns could be caused by the roof sheet metal no longer being attached fully to the roof bows (1). On trucks with a sunroof, it may be noticed that the rear edge of the sunroof glass is considerably lower than the roof (2). This is due to the roof sheet metal being detached from the roof bow directly behind the sunroof opening (3).
Object ID: 3973291Click here for detailed picture of the image.
Object ID: 3973293Click here for detailed picture of the image.
Object ID: 3973294Click here for detailed picture of the image.
Recommendation/Instructions
To correct this concern, apply panel vibration control material between the roof bow and roof sheet metal, along with foam shim material when necessary.
Remove the headliner to access the underside of the roof. Inspect all 4 roof bows for insufficient bonding to the roof sheet metal (4). Any roof bow that is not bonded to the sheet metal will need to be repaired.
Object ID: 3973295Click here for detailed picture of the image.
Use the following repair for all 4 bows on trucks without a sunroof, and for the 3 rear bows on trucks with a sunroof:
Use a plastic scraper or similar tool to remove the old foam. Measure the gap between the top of the roof bow and bottom of the roof sheet metal. If the gap is 1/4" (6mm) or greater, use a combination of 3/4" wide by 5/16" or 7/16" thick foam shim material (as listed below) to fill the gap between the roof bow and the sheet metal. Care should be taken to add only the correct thickness of foam to fill the gap so it does not push up on the roof. Cut the foam into 5 inch lengths and evenly place in five spots along the roof bow. With the foam shim material in place, or if the gap is less than 1/4" (6mm), use the panel control vibration material (as listed below) to fill the voids between the roof bow and sheet metal. In some cases, it may take a couple layers of material to fill the void.
Repair for 1st bow on trucks with a sunroof:
Using a plastic scraper or similar tool, remove the old foam. Use the panel control vibration material (listed below) and apply along the top of the 1st roof bow. Obtain two 2x4 pieces of wood long enough to span the opening of the sunroof. Wrap one of the 2x4's with a cloth to protect the roof paint and place it on top of the roof, see NOTE below. Place the second 2x4 underneath the roof bow, sandwiching the roof sheet metal and roof bow between the two pieces of wood. Clamp everything together using three C-clamps as shown in the photo below (5 & 6). The clamps will need to stay in place until the panel control vibration material is dry.
Note: When placing the cloth wrapped 2x4 on the top/roof, pay close attention that it is far enough forward so that the 2x4's rear edge does not contact the roof's raised ribs. The roof ribs may be damaged/dented if the 2x4 is placed on them when clamped down
Object ID: 3973296Click here for detailed picture of the image.
