Series 50 – Section 26.2 Improper Lubricating Oil Viscosity

Section 26.2
Improper Lubricating Oil Viscosity

To determine if improper lubricating oil viscosity is causing low oil pressure, perform the following: ‪

1. Acquire a lubricating oil sample from the engine oil pan.
2. Submit oil sample for an ASTM test analysis.
   1. If engine oil sample meets ASTM specifications, listed in Table "Compression Pressures at Various Altitudes" (refer to "29.2 Cylinder Compression Test" ), check to determine if lubricating oil is diluted with fuel or coolant; refer to "26.3 Lubricating Oil Diluted With Fuel Oil or Engine Coolant" .
   2. If engine oil sample did not meet ASTM specifications, listed in Table "Compression Pressures at Various Altitudes" (refer to "29.2 Cylinder Compression Test" ), refer to "26.2.1 Lubricating Oil Replacement" .

Section 26.2.1
Lubricating Oil Replacement

Perform the following steps to replace engine oil:‪

1. Drain and refill engine with new lubricating oil; refer to "13.5.1 Lubricating Oil" .
2. Verify lubricating oil replacement, refer to "26.2.1.1 Test Engine with Replaced Lubricating Oil" .

Section 26.2.1.1
Test Engine with Replaced Lubricating Oil

Perform the following to determine if replaced lubricating oil resolved low oil pressure:‪

1. Install the Diagnostic Data Reader to the vehicles Display Data Line Adaptor, see Figure "Typical Display Data Line Adaptor" ; refer to OEM guidelines.
2. Start and run engine speed at 1800 r/min.
3. Visually examine the DDR for oil pressure reading.
   1. If the DDR indicates oil pressure greater than 241 kPa (35 lb/in.² ), at 1800 r/min, shut down the engine and disconnect the DDR. No further troubleshooting is required.
   2. If the DDR indicates oil pressure less than 241 kPa (35 lb/in.² ), at 1800 r/min, shut down the engine and disconnect the DDR. Check the lubricating oil for fuel and water dilution; refer to "26.3 Lubricating Oil Diluted With Fuel Oil or Engine Coolant" .