MBE 900

Section 15.7 Excessive Oil Consumption

Section 15.7
Excessive Oil Consumption

DDC recommends a vehicle accumulate at least 20,000 miles (or 2nd oil change) for oil consumption to stabilize. Oil consumption rates above 700 miles/quart are considered normal. A high mileage engine will tend to be less. There are several causes for excessive oil consumption. These probable causes are:‪

  • Miscalibrated Dipstick
  • External Oil Leaks
  • Leaking Oil Heat Exchanger Core
  • Defective Air Compressor
  • Defective Turbocharger
  • Worn or Damaged Valve or Cylinder Kit

Section 15.7.1
Troubleshooting Procedure for Miscalibrated Dipstick

To determine if an overfilled crankcase is causing excessive oil consumption, perform the following:‪

  1. Ensure the vehicle is parked on level ground.
  2. Drain the oil pan. Refill oil pan to the proper capacity. Refer to "13.1.4 Engine Oil and Filter Changing" .
    1. If a calibration check indicates that the oil level is off by more than 2.0 mm (0.079 in.), contact Detroit Diesel Customer Support Center at 313-592-5800.
    2. Check for oil leaks; refer to "15.7.2 Troubleshooting Procedure for External Oil Leaks" .

Section 15.7.2
Troubleshooting Procedure for External Oil Leaks

To determine if oil leaks are causing excessive oil consumption, perform the following:‪

  1. Steam clean the engine.
    warning

    PERSONAL INJURY

    To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  2. Start and run the engine to operating temperature: 88°C (190°F).
  3. Check for leaks at oil lines, connections, mating joints, seals, and gaskets.
    1. If no oil leaks are found, shut down the engine and check for a leaking oil cooler core; refer to "15.7.4 Troubleshooting Procedure for a Leaking Oil Heat Exchanger Core" .
    2. If oil leaks are found, shut down the engine; refer to "15.7.3 Engine Oil Leak Repair" .

Section 15.7.3
Engine Oil Leak Repair

Perform the following steps, as necessary, to resolve engine oil leaks:‪

  1. Repair or replace components leaking oil; refer to chapter "3 Lubrication System" .
  2. Verify repairs made to correct oil leaks; refer to "15.7.3.1 Test Engine with Repairs Made to Correct Oil Leaks" .
Section 15.7.3.1
Test Engine with Repairs Made to Correct Oil Leaks

Perform the following steps to determine if the repairs resolved the oil leaks:‪

warning

PERSONAL INJURY

To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  1. Start and run the engine to operating temperature: 88°C (190°F).
  2. Shut down the engine.
  3. Check the engine for oil leaks.
    1. If no oil leaks are observed, check for a leaking oil heat exchanger core; refer to "15.7.4 Troubleshooting Procedure for a Leaking Oil Heat Exchanger Core" .
    2. If external oil leaks are present, refer to "15.7.3 Engine Oil Leak Repair" and repeat.

Section 15.7.4
Troubleshooting Procedure for a Leaking Oil Heat Exchanger Core

To determine if a leaking oil heat exchanger core is causing excessive oil consumption, perform the following:‪

  1. Check for oil in the engine coolant or radiator.
    1. If oil is present in either the engine coolant or radiator; go to step 2 .
    2. If no oil is present in either the engine coolant or radiator, check for a defective air compressor; refer to "15.7.5 Troubleshooting Procedure for a Defective Air Compressor" .
  2. Remove the oil heat exchanger core and housing.
  3. Clean both the oil side and water side of the oil heat exchanger core.
  4. Visually inspect the core for cracks.
    1. If cracks are present, replace oil heat exchanger core. Refer to "3.6 Heat Exchanger" . Verify the replacement of the oil heat exchanger core, refer to "15.7.4.1 Test Engine with New Oil Heat Exchanger Core" .
    2. If no cracks are present, complete a lube oil consumption report; call the Detroit Diesel Customer Support Center at 313-592-5800 for a form.
Section 15.7.4.1
Test Engine with New Oil Heat Exchanger Core

Perform the following steps to determine if the replaced oil heat exchanger core reduced the oil consumption:‪

warning

PERSONAL INJURY

To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  1. Start and run the engine to operating temperature: 88°C (190°F).
  2. Shut down the engine.
  3. Check the engine coolant for the presence of oil.
    1. If no oil is present in the coolant, perform a lube oil consumption test report; refer to "15.7.4.2 Test Engine for Reduced Oil Consumption" .
    2. If oil is present in the coolant, check for a defective turbocharger. Refer to "15.7.6 Troubleshooting Procedure for a Defective Turbocharger" .
Section 15.7.4.2
Test Engine for Reduced Oil Consumption

Perform a lube oil consumption report; call the Detroit Diesel Customer Support Center at 313-592-5800 for a form.‪

    Review the oil consumption report.‪

  1. If the oil consumption report data is within specifications, check for defective air compressor; refer to "15.7.5 Troubleshooting Procedure for a Defective Air Compressor" .
  2. If the oil consumption report data is not within specifications, call Detroit Diesel Customer Support Center at 313-592-5800.

Section 15.7.5
Troubleshooting Procedure for a Defective Air Compressor

To determine if a defective air compressor is causing excessive oil consumption, perform the following:‪

  1. Perform a crankcase pressure test and record the test results. Refer to "15.4.10.1 Crankcase Pressure Test" .
  2. Disconnect the air discharge line from the air compressor. See Figure "Air Line Attachments" ; refer to "10.1.1 Air Compressor Removal" .
    Click to see this graphic in a separate window

     1. Discharge Port‪

     4. Unloader Port‪

     2. Unloader Air Line‪

     5. Discharge Air Line‪

     3. Intake Air Line‪

     6. Air Compressor‪

    Figure 1. Air Line Attachments

  3. Repeat step 1 and record the results.
  4. Compare the results of test one with test two.
    1. If the engine crankcase pressure remained the same, check the turbocharger; refer to "15.7.6 Troubleshooting Procedure for a Defective Turbocharger" .
    2. If the engine crankcase pressure decreased, replace the air compressor; refer to "10.1.1 Air Compressor Removal" . Verify the replaced (or new) air compressor, refer to "15.7.5.1 Test Engine with Repaired Air Compressor" .
Section 15.7.5.1
Test Engine with Repaired Air Compressor

Perform the following steps to determine if the replaced (or new) air compressor resolved the excessive crankcase pressure:‪

warning

PERSONAL INJURY

To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  1. Start and run the engine.
  2. Perform a crankcase pressure test. Refer to "15.4.10.1 Crankcase Pressure Test" .
    1. If the engine crankcase pressure exceeds 0.62 kPa (2.5 in. H2 O), shut down the engine. Check for defective turbocharger. refer to "15.7.6 Troubleshooting Procedure for a Defective Turbocharger" .
    2. If the engine crankcase pressure is within 0.62 kPa (2.5 in. H2 O), shut down the engine; no further troubleshooting is required.

Section 15.7.6
Troubleshooting Procedure for a Defective Turbocharger

To determine if a defective turbocharger is causing excessive oil consumption, perform the following:‪

  1. Remove the turbocharger drain line connected to the crankcase and place the drain line into a suitable container.
  2. Perform a crankcase pressure test. Refer to "15.4.10.1 Crankcase Pressure Test" .
    1. If the engine crankcase pressure is less than 0.62 kPa (2.5 in. H2 O), shut down the engine. Replace the turbocharger; refer to "6.4.2 Turbocharger Removal" . Verify the replacement of the turbocharger, refer to "15.7.6.1 Test Engine with New Turbocharger" .
    2. If the engine crankcase pressure indicates no change, shut down the engine. Check for worn or damaged valve or cylinder kit. Refer to "15.7.7 Troubleshooting Procedure for Worn or Damaged Valve or Cylinder Kit" .
Section 15.7.6.1
Test Engine with New Turbocharger

Perform the following steps to determine if a new turbocharger resolved the excessive crankcase pressure:‪

  1. Remove the turbocharger drain line connected to the crankcase and place the drain line into a suitable container.
  2. Perform a crankcase pressure test. Refer to "15.4.10.1 Crankcase Pressure Test" .
    1. If the engine crankcase pressure is greater than 0.62 kPa (2.5 in. H2 O), check for worn or damaged valve or cylinder kit; shut down the engine. Refer to "15.7.7 Troubleshooting Procedure for Worn or Damaged Valve or Cylinder Kit" .
    2. If the engine crankcase pressure is 0.62 kPa (2.5 in. H2 O) or less, no further troubleshooting is required. Shut down the engine.

Section 15.7.7
Troubleshooting Procedure for Worn or Damaged Valve or Cylinder Kit

A loss of cylinder pressure can cause increased oil consumption. The detection and elimination of cylinder pressure losses is vital to engine life and efficient operation. To assist the mechanic in effectively measuring the loss of cylinder pressure, and locating the source of abnormal leaks in individual cylinders, the following test procedure has been developed:‪

  1. Move the vehicle requiring test to the chassis dynamometer; refer to OEM guidelines.
  2. Disconnect the air compressor and remove; refer to "10.1.1 Air Compressor Removal" .
    warning

    PERSONAL INJURY

    To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  3. Start the engine.
  4. Run the engine and bring the engine coolant temperature to normal operating range, approximately 88-96°C (190-205°F).
  5. Run the vehicle to full load and rated speed.
  6. Perform a crankcase pressure test. Refer to "15.4.10.1 Crankcase Pressure Test" .
  7. Shut down the engine.
  8. Remove the vehicle from the chassis dynamometer.
  9. Review the crankcase pressure test results.
    1. If the crankcase pressure exceeds 0.62 kPa (2.5 in. H2 O), repair worn or damaged valve(s) or cylinder kit; refer to "15.7.8 Worn or Damaged Valve(s) or Cylinder Kit(s) Repair" .
    2. If the crankcase pressure was less than or equal to 0.62 kPa (2.5 in. H2 O), perform a cylinder compression test. Refer to "1.2.2.2 Compression Testing" .
  10. Compare the cylinder compression test results to specifications as listed in Table "Compression Testing" .
    1. If the cylinder compression is below specifications, repair worn or damaged valve(s) or cylinder kit; refer to "15.7.8 Worn or Damaged Valve(s) or Cylinder Kit(s) Repair" .
    2. If the cylinder compression is within specifications, call Detroit Diesel Customer Support Center at 313-592-5800.

Section 15.7.8
Worn or Damaged Valve(s) or Cylinder Kit(s) Repair

Perform the following steps to repair worn or damaged valve(s) and cylinder kit(s):‪

  1. Remove the cylinder head; refer to "1.2.1 Cylinder Head Removal" .
  2. Inspect the cylinder head for worn or damaged valves; refer to "1.17 Valves" .
  3. Inspect the cylinder kit components for worn or damaged liners; pistons or piston rings; refer to "1.15.3.1 Piston and Piston Ring Cleaning, Inspection, and Measuring" .
  4. Replace damaged cylinder kit components.
  5. Verify repairs made to cylinder head valve(s) or cylinder kit components; refer to "15.7.8.1 Test Engine with Repaired Cylinder Head Valve(s), and Cylinder Kit" .
Section 15.7.8.1
Test Engine with Repaired Cylinder Head Valve(s), and Cylinder Kit

To determine if the cylinder head valve and cylinder kit repair resolved starting difficulty, perform the following steps:‪

warning

PERSONAL INJURY

To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  1. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting in required.
  2. If the engine fails to start and run, call the Detroit Diesel Customer Support Center at 313-592-5800.


MBE 900 Service Manual - 6SE414
Generated on 10-13-2008

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