Some 1983-1986 C/K Trucks may experience a condition where the grille mounting tabs exhibit cracks or break off To address this condition, the valance panel and radiator grille assembly have been revised interim 1986. The changes incorporated in these parts will allow for the expansion and contraction of the grille assembly due to temperature changes. The revised valance panel and radiator grille assembly were changed in production begin- ning with the following vehicle identification break- points.
Assembly Plant GMC -------- ---- Janesville GJ506647 Flint GF706504 (Pick-up) GF505772 (Suburban) Oshawa G1512525 St. Louis GS507791
The valance panel on affected 1983-86 C/K Trucks can be modified by slotting the two outboard grille mounting holes following the service procedure below. Refer to the parts list for the revised assemblies.
1. Remove headlamp bezels and grille. Discard grille assembly if cracked or broken.
2. Remove the plastic nut from the two outboard mounting holes of the front valance panel (see Figure No. 1.).
3. Use a nibbling tool to slot the two outer valance panel holes .1 inch on each side, in the cross vehicle direction (see Figure No. 1.). This will change the square .3 x .3 inch hole to a rectangular .3 x .5 inch hole.
4. Paint exposed steel edges as required to prevent corrosion.
5. Reinstall plastic nuts. Install appropriate grille assembly and nuts from part numbers listed. Reinstall headlamp bezels.
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.