OIL CANNING NOISE ON ROOF DIAGNOSIS & SERVICE PROCEDURE

Subject: OIL CANNING NOISE ON ROOF PANEL

Model and Year: 1990 CORSICA/BERETTA

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 90- 388-10, DATED NOVEMBER 1990. ART HAS BEEN ADDED. ALL COPIES OF 90-388-10 SHOULD BE DISCARDED.

Some 1990 L-body vehicles may have a gap between the roof bows and the roof panel which may result in a drumming/oil canning noise on some road surfaces. To eliminate this condition apply 3M Foam Tape # 06370 (or equivalent) between roof bow and roof panel; and urethane adhesive (contained in kit) GM P/N 12345633 (or equivalent) between headers and roof panel.

1. Remove headliner from vehicle, refer to Roof (Section 10-8) in the 1990 Chevrolet Corsica/Beretta Service Manual.

2. Inspect roof bows to roof panel for adhesive sealer. Sealer should be present and contacting roof panel from side to side.

3. If adhesive sealer is not present or contacting roof panel, fabricate shim blocks (wood or other suitable material) large enough to slightly increase void space between roof bow and roof panel, refer to Figure.

4. Install shim blocks between bows and roof panel on both sides of bow (front and rear), slightly increasing space between roof bow and roof panel.

5. Cut strips of 3M Scotchfoam Black Vinyl Foam Tape approximately 10 cm (4 in.) long and attach to top of roof bows at four locations on each side of bows, refer to Figure.

6. Remove shim blocks; foam tape should be compressed slightly between bow and roof panel.

7. Inject urethane every 10 cm (4in.) along groove in front and rear headers. Use only enough urethane to contact header and roof panel, refer to Figure.

8. Install headliner into vehicle, refer to Roof (Section 10-8) in the 1990 Chevrolet Corsica/Beretta Service Manual.

Labor Operation Number: T1427

Labor Time: 1.5 Hours

Trouble Code: 92

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.