CAMPAIGN: AIR INJECTOR PIPE CORROSION/REPAIR REVISION

MODELS: 1983 CABALLERO EQUIPPED WITH 3.8L ENGINE (VIN CODE A) AND CALIFORNIA EMISSIONS (RPO NB2)

General Motors has determined that certain 1983 GMC Caballero model vehicles equipped with RPO LD5 3.8L engine and California emissions may be emitting pollutants in excess of California emission standards. This may be attributed to the air injection tube corroding with increased mileage and exposure.

To correct this condition, the AIR injection tube and AIR injection check valve will be inspected and replaced, if required. In addition, the carburetor primary vacuum break is to be inspected for proper operation. When required, the primary vacuum break, if found to be inoperative, will be replaced.

VEHICLES INVOLVED

Involved are certain 1983 GMC Caballero model vehicles equipped with RPO LD5 3.8L engine (VIN Code A) and Califomia emissions (RPO NB2).

Plant From Through ----- ---- ------- Arlington SOP EOP

The specific vehicles invloved in this cam- paign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished to all involved dealers with the campaign bulletin.

DEALER CAMPAIGN RESPONSIBLITY

Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward.

Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your dealership for service in the future, you should take the steps necessary to ensure the campaign correction has been made before reselling or releasing the vehicle.

Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer and arrangements made to make the required correction according to instructions contained in this bulletin.

If no owner's name and address were available to GMC Truck Division at the time of campaign initiation, the dealer will determine the owner's name and address from the dealership sales records. Please provide this information directly on the second copy of the listing next to the applicable VIN so that our records may be updated and the appropriate notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign envelopes.

GMC Truck Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by GMC Truck Division (see copy of owner letter included with this bulletin). A listing of owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing may contain owner names and addresses obtained from state motor vehicle registration records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to this campaign.

SERVICE PROCEDURE

1. Open hood and install fender covers. Remove air cleaner assembly.

2. Inspect and replace, if necessary, AIR injector pipe and AIR injector check valve (See Figure No. 1):

a. Inspect AIR injector pipe for color. If pipe is black, new pipe has been installed, proceed to Step 3.

b. If pipe is corroded or silver color, replace AIR injector pipe and check valve. Use a back up wrench to loosen pipe fitting from intake manifold fitting. Remove clamp from hose end at check valve. Remove AIR injector pipe and AIR check valve.

c. Install new AIR injector pipe, AIR check valve, and clamp.

3. Inspect and replace, if necessary, primary (front) vacuum break:

a. Check primary (front) vacuum break for leakage by applying vacuum with hand vacuum device (J-23738) or equivalent. The unit should hold the vacuum level. If vacuum level is held, proceed to Step 4.

b. If vacuum level is not held, replace primary (front) vacuum break unit.

c. Check vacuum break for proper setting (28 deg.). If adjustment is required, reset using primary vacuum break adjusting procedure shown in Figure No. 2.

4. Reinstall air cleaner assembly and check engine operation. Check AIR injector pipe and check valve fittings for leakage.

5. Remove fender covers.

6. Close hood.

PARTS INFORMATION

Parts are to be obtained from General Motors Service Parts Operation (GMSPO). To ensure that these parts will be obtained as soon as possible, they should be ordered from GMSPO on a C.I.O. order with NO special instruction code, but order on an advise code (2).

PART NUMBER DESCRIPTION QTY/VEH. ------ ----------- -------- 25518944 AIR Pipe Assembly I (AR) 22048579 AIR Check Valve I (AR) 17067466 Vacuum Break, Primary I (AR) 10031017 Clamp (3/4" to 1 3/4") 1 (AR)

WARRANTY INFORMATION

Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed under this campaign.

LABOR OPERATION *TIME TROUBLE NUMBER DESCRIPTION ALLOWANCE CODE ------ ----------- --------- ---- V4370 Inspect Only .2 Hr 96

V4371 Inspect & replace .5 Hr 96 AIR injector pipe and check valve

V4372 Inspect & replace .3 Hr 96 primary vacuum break

V4373 Inspect & replace .6 Hr 96 AIR injector pipe, AIR check valve & primary vacuum break

* For dealer to receive Administrative Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.

CAMPAIGN IDENTIFICATION LABEL

Each vehicle corrected in accordance with the instructions outlined in this product campaign bulletin will require a "Campaign Identification Label". Each label provides a space to include the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or ball point pen.

Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner.

Apply "Campaign Identification Label" only on a clean dry surface.

ADMINISTRATIVE PROCEDURE

Procedures covering this campaign are outlined in Section V of your dealership's "GMC Truck Claims Processing Manual" #P 8719.

GMC TRUCK CUSTOMER ASSISTANCE REPRESENTATIVES

Use the phone number and address listing below to contact GMC Truck Customer Assistance Representatives. Refer to the map to determine your geographic area. When writing use the mail code assigned to your area.

GMC Truck Customer Service Department Mail Code

31 Judson Street Pontiac, MI 48058

Geographic Area Telephone No. Mail Code --------------- --------------- --------- A (415) 498-5225 1606-06 B (805) 373-9521 1606-06 C (303) 930-5890 1606-08 D (214) 659-5154 1606-07 E (913) 451-4173 1606-08 F (312) 961-6465 1606-03 G (713) 591-0804 1606-07 H (313) 456-3553 1606-03 I (201) 993-4065 1606-04 J (301) 258-1480 1606-04 K (901) 756-3453 1606-05 L (404) 257-3666 1606-05

NOTE: Residents of Alaska and Hawaii should call GMC Truck Customer Service Department (313) 456-4547 or write to the address above without Mail Code.

Dear GMC Truck Owner:

This notice is sent to inform you that GMC Truck Division is initiating a recall campaign that includes your vehicle.

REASON FOR THIS RECALL

General Motors has determined that certain 1983 Caballero model vehicles equipped with 3.8L engine and California emission equipment, may be emitting pollutants in excess of California emission standards. This may be attributed to the AIR injection tube corroding with increased mileage and exposure.

WHAT WE WILL DO

The AIR injection tube and AIR injection check valve will be inspected and, when necessary, replaced. In addition, the carburetor primary vacuum break will be inspected. When required, the primary vacuum break, if found to be inoperative, will be replaced. This service will be performed for you at no charge.

WHAT YOU SHOULD DO

Please contact your GMC Truck dealer to arrange a service date. Instructions for making this correction have been sent to your GMC Truck dealer. The labor time necessary to inspect your vehicle is approximately 15 minutes. If parts are replaced, up to approximately 40 minutes will be required to service your vehicle. In either case, please allow some additional time for the dealer to process your vehicle.

Should your dealer not schedule a service date within a reasonable time, you should contact your GMC Truck Zone Office by telephone for assistance. The telephone numbers of the Zone Offices are on the reverse side for your convenience.

The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction to your vehicle in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid owner reply card and returning it to us.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.

GMC TRUCK DIVISION GENERAL MOTORS CORPORATION

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.