Instruments - False High Oil Pressure Gauge Readings
87buick14Bulletin: 88-6-3
Date: Dec., '87
Ref. No. 88-015-6
Corp. Ref. No. 806401
SUBJECT: FALSE HIGH OIL PRESSURE GAUGE READINGS
MODELS AFFECTED: 1988 VEHICLES EQUIPPED WITH 3.8L LG3 (VIN CODE 3), 3800 LN3 (VIN CODE C), AND 3.0L LN7 (VIN CODE L) V-6 ENGINES
Some of the above listed vehicles may exhibit false high oil pressure gauge readings during normal engine operation.
FIGURE 1:
This condition may be due to a loss of ground to the oil pressure switch mounted in the oil filter adapter (Refer to Figure 1). The condition may be confirmed and corrected by the following procedure:
1. Verify that the oil pressure gauge is reading high.
NOTICE: Normal engine oil pressure should be approximately 20 psi at idle in drive, with the engine at operating temperature; and approximately 45 psi at 2000 E.R.P.M. in park with the engine at operating temperature.
2. Ground the base of the [1][2]oil pressure sensor to the negative battery terminal or a known good chassis ground.
3. If procedure Step 2 causes a correction in the pressure gauge reading, remove and discard the four (4) bolts that attach the oil filter adapter to the front cover. Install a new oil filter adapter gasket, Part Number 25529916 and replace the original bolts with four (4) bolts, Part Number 25534181. Torque the new bolts to 17 N-m (12.5 ft.lbs.).
4. Verify that the oil pressure gauge is reading correctly and inspect the oil filter adapter gasket area for leaks.
If the above does not cause a change in the pressure gauge reading, or if the new reading is below recommended minimum oil pressures; follow the normal service diagnostic procedure for the engine oiling system.