In the event of leakage, check for following conditions:
1. CONDITION: Water entry between rear compartment lid opening weatherstrip and body at right and left front corners (radius areas) of rear compartment lid opening.
CAUSE: Skip or void in sealant between weatherstrip and body flange.
CORRECTION: Flow test with water hose, no nozzle and low pressure. If a leak is found, seal with 3M-8011 or equivalent. After sealant is dry, reflow test.
2. CONDITION: Leakage between rear compartment lid and weatherstrip (with properly fitted lid) especially in high pressiare car wash.
CAUSE: Insufficient weatherstrip contact to lid.
CORRECTION: Use dollar bill or paper strip test, closing lid and pulling on paper to test weatlierstrip for contact (compression). If location of minimal resistance is found (indicating insufficient compression of weatherstrip to lid), move weatherstrip and sheet metal return flange upward with rubber mallet by hitting under side of flange in that area. Retest for contact.
3. CONDITION: Leakage through joint, right or left quarter panels to rear compartment front panel (aft of back window), in rear lid opening area.
CAUSE: Skips or voids in sealant.
CORRECTION: Air hose test, apply soapy water to joint area, apply air pressure from underside, not to exceed 30 psi . Observe for bubbles; if found, rinse and dry area to be sealed. Seal with 3M Joint and Seam Sealant, either 08646 White, 08648, black, or equivalent.
4. CONDITION: (Coupe Style Only) When opening rear compartment lid, water may spill out from rear area of lid between inner and outer panels.
CAUSE: Check for absence of one or both sealing plugs located at rear corners of lid inner panel, outboard of weatherstrip contact area. Plugs. are approximately 32mm, 1 1/4" in diameter; one (1) used in each rear corner. Their function is to seal access holes, which are used to gain access to optional spoiler attaching nuts, if so equipped.
CORRECTION: Install plug(s), Part Number 4768119.
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.