LOW ENGINE OIL PRESSURE ALARM ACTIVATED

SUBJECT: LOW ENGINE OIL PRESSURE ALARM ACTIVATED AND DASH TELLTALE GOES ON INTERMITTENTLY (RELOCATE OIL PRESSURE SENDER)

MODELS: 1990-95 TOPKICK/KODIAK, B7 SCHOOL BUS, OR P6 WITH 6.0L OR 7.0L GAS ENGINES (VINS M, P - RPOS LR0, LS0)

CONDITION:

THE LOW ENGINE OIL PRESSURE ALARM MAY ACTIVATE AND DASH TELLTALE MAY GO ON INTERMITTENTLY.

CAUSE:

THE OIL PRESSURE SENDER MAY BE LOCATED TOO FAR FROM THE ENGINE OIL PUMP TO GIVE AN ACCURATE READING. DETERMINE THE TRUE ENGINE OIL PRESSURE BY FOLLOWING STEP 1 BELOW.

CORRECTION:

RELOCATE THE OIL PRESSURE SENDER FROM THE FRONT OF THE ENGINE TO THE REAR OF THE ENGINE. PLUG THE HOLE AT THE FRONT OF THE ENGINE.

SERVICE PROCEDURE

1. WITH THE ENGINE OFF: - INSTALL A MECHANICAL GAUGE IN THE PRESSURE TAP JUST ABOVE THE OIL FILTER BOSS ON THE SIDE OF THE BLOCK. - START THE ENGINE AND CHECK ENGINE OIL PRESSURE. - COMPARE WITH ENGINE OIL PRESSURE GAUGE READING ON THE INSTRUMENT PANEL. A) IF THERE IS AT LEAST 10 PSI DIFFERENCE, AND THE ENGINE OIL PRESSURE ALARM AND TELLTALE LAMP COME ON INTERMITTENTLY, GO TO STEP 2. B) IF THERE IS NO DIFFERENCE IN THE READINGS OR THEY ARE WITHIN 10 PSI OF EACH OTHER, REFER TO THE SERVICE MANUAL TO DIAGNOSE AND REPAIR THE LOW ENGINE OIL PRESSURE CONDITION. 2. REMOVE PLUG FROM ENGINE AT THE DESIGNATED NEW LOCATION FOR THE OIL PRESSURE SENDER (FIGURE 1). 3. APPLY SEALER TO BUSHING (ITEM #3 IN FIGURE 1). 4. INSTALL BUSHING TO ENGINE (FIGURE 1). 5. APPLY SEALER TO FITTING (FIGURE 1). 6. INSTALL FITTING TO BUSHING. - FOR P6, C6, C7 THE FITTING END SHOULD BE INDEXED POINTING TO THE RIGHT TO AVOID INTERFERENCE WITH THE FUEL LINES (FIGURE 1). - FOR B7 MODELS, THE FITTING SHOULD BE INDEXED POINTING TO THE LEFT (NOT PICTURED). 7. REMOVE SENDER FROM ORIGINAL LOCATION (FIGURE 2). 8. APPLY SEALER TO SENDER. 9. INSTALL THE SENDER IN THE FITTING FROM STEP 6 (FIGURE 1). 10. CUT ALL FOUR WIRES TO THE SENDER. - SPLICE IN EXTRA LENGTH OF WIRE TO ENSURE THE WIRES CAN BE ROUTED TO THE NEW LOCATION. - THE SPLICES SHOULD BE MADE BETWEEN THE SENDER AND THE ENGINE HARNESS. - USE HEAT SHRINK TUBING TO PROTECT THE SPLICES. - SHIELD THE NEW SECTION OF WIRING WITH PLASTIC CONVOLUTED TUBING, AVAILABLE IN THE STANDARD PARTS CATALOG FROM GMSPO. 11. AFTER RELOCATION OF THE SENDER, INSTALL PLUG WITH SEALER IN THE ORIGINAL SENDER LOCATION AT THE FRONT OF THE ENGINE (FIGURE 1). 12. TAPE OR CLIP THE NEW SECTION OF WIRES ALONG EXISTING HARNESS. 13. CHECK THE OIL PRESSURE AGAIN WITH MECHANICAL GAUGE TO VERIFY THE FIX.

PARTS INFORMATION

P/N DESCRIPTION QTY 15660706 ELBOW FITTING (FOR NEW LOCATION) 1 12346004 PIPE SEALER WITH TEFLON (FOR BOTH LOCATIONS) 1 444094 COUPLING (TO PLUG OLD LOCATION) 1 121830 NIPPLE (TO PLUG OLD LOCATION) 1 9409927 FITTING (TO PLUG OLD LOCATION) 1 444024 BUSHING (FOR BOTH LOCATIONS) 1 (REUSE ORIGINAL BUSHING IF POSSIBLE) 15955709 ENGINE OIL PRESSURE SENDER 1 (REUSE ORIGINAL SENDER IF POSSIBLE)

IMPORTANT: A NEW SENDER MAY NOT BE REQUIRED IF RELOCATING EXISTING SENDER.

SIZE/COLOR WIRE C6, C7 B7 P6 .8 TAN 31" 46" 50" .8 BLACK 31" 46" 50" 1.0 GRAY 31" 46" 50" 1.0 ORANGE 31" 46" 50"

IMPORTANT: IT IS PREFERABLE TO USE THE CORRECT COLOR AND SIZE WIRES. HOWEVER, IF THE DEALERSHIP DOES NOT HAVE THE VARIOUS WIRE COLORS IN THE SPECIFIC SIZES NEEDED IN STOCK, IT IS CRITICAL TO USE THE CORRECT SIZE WIRE (.8 OR 1.0) WHEN SPLICING INTO THE EXISTING COLORED WIRES.

PARTS INFORMATION:

PARTS ARE EXPECTED TO BE AVAILABLE FROM GMSPO ON 3/6/95.

WARRANTY INFORMATION

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME N6270 WIRING AND/OR CONNECTOR REPAIR USE PUBLISHED N2220 SWITCH - REPLACE ENGINE OIL PRESSURE LABOR OPERATION TIME

FIGURES: 2

CAPTIONS: FIGURE 1 - NEW LOCATION FOR FITTING TO HOLD ENGINE OIL PRESSURE SENDER FOR C6, C7 MODELS FIGURE 2 - ORIGINAL LOCATION OF ENGINE OIL PRESSURE SENDER

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.

COPYRIGHT 1995 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.