Oil Pressure Gauge - Flutters, or May Read High

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GMC NUMBER: 91-6A-180

GROUP: 6A Engine Mechanical

DATE: March, 1992

CORPORATE
NUMBER: 138304R


SUBJECT:
OIL PRESSURE GAGE FLUTTERS, OR MAY READ HIGH (REPLACE SENSOR)

MODELS:
1990-91 S/T, ML, C/K, R/V/G/P

THIS BULLETIN CANCELS AND REPLACES GMC TRUCK BULLETIN 91-6A-157, PUBLISHED IN NOVEMBER 1991. IT WAS REVISED TO UPDATE PART NUMBER INFORMATION FOR P-TRUCKS AND DIESEL ENGINES. ALL COPIES OF 91-6A-157 SHOULD BE DISCARDED.


On S/T, M/L, C/K, R/V, G, and P vehicles with gages, the oil pressure gage may flutter or show unusually high oil pressure (full scale), because the internal resistance wire in the sensor may not be properly supported, resulting in an intermittent open condition.

SERVICE PROCEDURE:
Check for normal causes of high oil pressure gage readings (high resistance or open circuit), such as a poor ground path caused by loose sensor mounting, oil cooler adapter loose, or poor electrical connections. If no cause can be found, replace the [1][2]oil pressure sensor with the correct new part number from the chart.





SERVICE PARTS INFORMATION:
NEW [1][2]OIL PRESSURE SENSOR PART NUMBERS
- 1990-91 Models


* For further details, refer to GMC Truck Bulletin 92-8C-30, published January 1992. Parts are currently available from GMSPO.

WARRANTY INFORMATION:
Use existing labor operation N2220.