Home » ISX11.9 CM2250 - Service Manual » Cummins ISX11.9 CM2250 – Service Manual 007-044   Lubricating Oil Contamination

Cummins ISX11.9 CM2250 – Service Manual 007-044   Lubricating Oil Contamination

Initial Check

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 CAUTION 

Diluted lubricating oil can cause severe engine damage.

Check the condition of the lubricating oil.

  • Thin, black lubricating oil is an indication of fuel in the oil. The oil will have a strong fuel aroma.
  • Milky discoloration is an indication of coolant in the lubricating oil.

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General Information

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A used oil analysis can help diagnose internal damage and determine if it was caused by one of the following:

  • Oil diluted with dust
  • Oil diluted with coolant
  • Oil diluted with fuel
  • Extended oil drain interval
  • Possible engine wear.

Use the following chart to assist with diagnosis.

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Material in Sample
Likely Cause
Action
Silicon
Dust ingestion via air intake
Calcium/Sodium
Coolant leak
Use the Coolant-Diluted Lubricating Oil section in this procedure.
Fuel
Fuel leak
Use the Fuel-Diluted Lubricating Oil section in this procedure.
Soot
Extended oil drain interval
Change the oil or shorten the oil change intervals.
Wear Metal
Possible engine wear

Coolant Diluted Lubricating Oil


Coolant in the lubricating oil can be caused by:

  1. Expansion plugs leaking
  2. Lubricating oil cooler element leaking
  3. Damaged cylinder head or gasket
  4. Cracked engine block
  5. Casting porosity
  6. Exhaust gas recirculation (EGR) cooler.

Use the Coolant Loss – Internal symptom tree (T021) in Section TS for specific check steps.

 
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Fuel Diluted Lubricating Oil


Fuel dilution is limited to six sources:

  1. Injection pump shaft seal
  2. Fuel leaking by the piston rings
  3. Engine idle time excessive
  4. A crack in the cylinder head from the fuel filter location to the air intake
  5. Injector leakage
  6. Porosity in the cylinder head.

Use the Fuel in the Lubricating Oil symptom tree (T092) in Section TS for specific check steps.

 
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Last Modified:  11-Jun-2010