Oil Pressure Diagnosis and Testing (LS3 with Z52 Option, LS7)

Special Tools

• EN-47971:  Oil Pressure Gauge Adapter
• J 21867:  Pressure Gauge

For equivalent regional tools, refer to Special Tools .

Fig 1: Oil Pressure Gauge Adapter And Pressure Gauge
Courtesy of GENERAL MOTORS CORP.
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 the oil level.
2. If required, add the recommended grade engine oil and fill the oil tank until the oil level measures full on the oil level indicator.
3. Run the engine briefly, 10-15 seconds, and verify low or no oil pressure on the vehicle gauge or lamp.
4. Listen for a noisy valve train or a knocking noise.
5. Inspect for the following conditions:
   • Oil diluted by water or glycol antifreeze
   • Foamy oil
6. Remove the oil filter and install the EN-47971:  adapter (1).
7. Install the J 21867:  gauge (2), or equivalent to the EN-47971:  adapter (1).
8. Run the engine and measure the engine oil pressure.
9. Compare the readings to Engine Mechanical Specifications (6.2L LS3) or Engine Mechanical Specifications (7.0L LS7) .
10. If the engine oil pressure is below specifications, inspect the engine for 1 or more of the following conditions:
    • Restricted engine oil tank screen
    • Collapsed or restricted oil hoses
    • Loose oil hose connections at the oil tank or oil pan
    • Damaged oil tank-to-hose or oil pan-to-hose O-ring seals
    • Oil pump worn or dirty

      Refer to Oil Pump Cleaning and Inspection (LS3 with Z52 Option, LS7) .

    • Oil pump-to-engine block bolts loose or oil pump mis-aligned to the oil pan rail

      Refer to Oil Pump and Crankshaft Oil Deflector Installation (LS3 with Z52 Option, LS7, LS9) .

    • Damaged oil pan gasket at oil pump sealing surface damaged
    • Malfunctioning oil pump pressure relief 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:  gauge, or equivalent, is within specifications, inspect for the following conditions:
    • Plugged or incorrect oil filter
    • Malfunctioning vehicle oil pressure gauge or engine oil pressure sensor

      Repair, as necessary.