For 1990-2009 cars

# INFO. ON SERVICE TOOL J 42907- OIL PRESSURE TESTING TOOL

#### SUBJECT: INFORMATION ON SERVICE TOOL J 42907 - OIL PRESSURE TESTING TOOL

#### MODELS: 1997-98 CHEVROLET CORVETTE 1998 CHEVROLET CAMARO 1988 PONTIAC FIREBIRD WITH 5.7L ENGINE (VIN G - RPO LS1)

THIS BULLETIN PROVIDES UPDATED INFORMATION REGARDING A NEW SERVICE TOOL, J 42907, WHICH CAN BE USED TO PERFORM ON-VEHICLE OIL PRESSURE TESTING ON ALL CORVETTE, CAMARO, AND FIREBIRD MODELS EQUIPPED WITH THE 5.7L (VIN G - RPO LS1) V-8 ENGINE.

PROCEDURE - OIL PRESSURE DIAGNOSIS AND TESTING

#### IMPORTANT: THE NEW SERVICE TOOL MUST BE USED IN CONJUNCTION WITH J 21867 - PRESSURE GAUGE AND HOSE ASSEMBLY OR EQUIVALENT.

1. WITH THE VEHICLE ON A LEVEL SURFACE, RUN THE VEHICLE FOR A FEW MINUTES, ALLOW ADEQUATE DRAIN DOWN TIME (2-3 MINUTES) AND MEASURE FOR A LOW OIL LEVEL.

2. IF REQUIRED, ADD THE RECOMMENDED GRADE ENGINE OIL AND FILL THE CRANKCASE UNTIL THE OIL LEVEL MEASURES FULL ON THE OIL LEVEL INDICATOR.

3. RUN THE ENGINE BRIEFLY (10-15 SECONDS) AND VERIFY IF LOW OR NO OIL PRESSURE ON THE VEHICLE GAUGE OR LIGHT.

4. LISTEN FOR A NOISY VALVE TRAIN OR A KNOCKING NOISE.

5. INSPECT FOR THE FOLLOWING: * OIL DILUTED BY WATER OR GLYCOL (ANTI-FREEZE) * FOAMY OIL

6. REMOVE THE OIL FILTER AND INSTALL THE J 42907.

7. INSTALL THE J 21867 OIL PRESSURE HOSE AND GAUGE ASSEMBLY, OR EQUIVALENT, TO THE J 42907.

8. RUN THE ENGINE AND MEASURE THE ENGINE OIL PRESSURE.

9. COMPARE THE READINGS TO ENGINE MECHANICAL SPECIFICATIONS.

10. IF THE ENGINE OIL PRESSURE IS BELOW SPECIFICATIONS, INSPECT FOR ONE OR MORE OF THE FOLLOWING: - OIL PUMP WORN OR DIRTY REFER TO OIL PUMP CLEAN AND INSPECT INFORMATION. - OIL PUMP TO ENGINE BLOCK BOLTS LOOSE REFER TO OIL PUMP, PUMP SCREEN AND DEFLECTOR INSTALLATION. - OIL PUMP SCREEN LOOSE, PLUGGED OR DAMAGED - OIL PUMP SCREEN O-RING SEAL MISSING OR DAMAGED - MALFUNCTIONING OIL PUMP PRESSURE REGULATOR VALVE - EXCESSIVE BEARING CLEARANCE - CRACKED, POROUS OR RESTRICTED OIL GALLERIES - OIL GALLERY PLUGS MISSING OR INCORRECTLY INSTALLED REFER TO ENGINE BLOCK PLUG INSTALLATION. - BROKEN VALVE LIFTERS - REPAIR AS NECESSARY 11. IF THE OIL PRESSURE READING ON THE J 21867, OR EQUIVALENT, IS WITHIN SPECIFICATIONS, INSPECT FOR THE FOLLOWING: - PLUGGED OR INCORRECT OIL FILTER AND/OR MALFUNCTIONING OIL BYPASS VALVE - MALFUNCTIONING VEHICLE OIL PRESSURE GAUGE OR SENSOR - REPAIR AS NECESSARY

**INSERT FIGURE XPOLS101**

FIGURES: 01 ATTACHMENTS: 00

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.

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