| • | J 21867 Pressure Gage | 
| • | J 42907 Oil Pressure Tester | 
| • | Oil diluted by water or glycol antifreeze | 
| • | Foamy oil | 
| • | Oil pump worn or dirty. Refer to Oil Pump Replacement, Oil Pump Disassemble and Oil Pump Cleaning and Inspection. | 
| • | Oil pump-to-engine block bolts loose. Refer to Oil Pump Replacement. | 
| • | Oil pump screen loose, plugged, or damaged. Refer to Oil Pump Suction Pipe and Screen Assembly Replacement. | 
| • | Oil pump screen O-ring seal missing or damaged. Refer to Oil Pump Suction Pipe and Screen Assembly Replacement. | 
| • | Oil pump pressure relief valve malfunction. Refer to Oil Pump Replacement. | 
| • | Engine bearing clearance excessive. Refer to Crankshaft and Bearing Cleaning and Inspection, Crankshaft and Bearing Installation and Piston, Connecting Rod, and Bearing Installation. | 
| • | Cracked, porous, or restricted oil galleries. | 
| • | Oil gallery plugs missing or incorrectly installed. Refer to Engine Block Assemble - Upper and Cylinder Head Assemble. | 
| • | Valve lifters broken. Repair, as necessary. Refer to Valve Lifter Replacement - Left Side and/or Valve Lifter Replacement - Right Side and Valve Lifters Cleaning and Inspection. | 
| • | Crankshaft balancer bolt missing, loose or under-torqued. | 
| • | Plugged or incorrect oil filter and/or malfunctioning oil bypass valve. Refer to Engine Oil and Oil Filter Replacement. | 
| • | Malfunctioning oil pressure gage or sensor. Repair, as necessary. Refer to Engine Oil Pressure Sensor and/or Switch Replacement. |