Skip to main content

MBE 900 EXCESSIVE BLUE SMOKE

There are several causes for excessive blue exhaust smoke. These probable causes are: ‪

  • Defective Turbocharger
  • Worn or Damaged Valve or Cylinder Kit

Troubleshooting Procedure for a Defective Turbocharger

To determine if a defective turbocharger is causing excessive blue exhaust smoke, perform the following: ‪

  1. Remove the charge air cooler inlet duct connected between the turbocharger and charge air cooler.
  2. Visually inspect the charge air cooler inlet duct.
    1. If excessive engine lube oil is present, refer to section .
    2. If minimal engine lube oil is present, check for worn or damaged valves or cylinder kit; refer to section .

Turbocharger Replacement

Perform the following steps to replace a defective turbocharger: ‪

  1. Remove the defective turbocharger from the engine; refer to section .
  2. Tag the removed turbocharger for remanufacture.
  3. Install a replacement turbocharger to the engine; refer to section .
  4. Verify replacement of the new turbocharger; refer to section .
Test Engine with Replaced Turbocharger

Perform the following steps to determine if a replaced turbocharger has resolved the excessive blue exhaust smoke condition: ‪

  1. Start and run the engine.
  2. Run the engine at idle speed with a no-load condition for approximately five minutes, allowing the engine coolant to reach normal operating range, approximately 88-96C (190-205F).
  3. Visually inspect the exhaust for excessive blue smoke.
    1. If the engine exhaust smoke emission appears normal, no further troubleshooting is required. Shut down the engine.
    2. If the engine exhaust smoke is excessively blue, shut down the engine. Check for worn or damaged valves or cylinder kit; refer to section .

Troubleshooting Procedure for a Worn or Damaged Valve or Cylinder Kit

To determine if a worn or damaged cylinder kit is causing excessive blue exhaust smoke, perform the following: ‪

  1. Move the vehicle requiring testing to the chassis dynamometer; refer to OEM guidelines.
  2. Disconnect and remove the air compressor; refer to section .
  3. Start the engine.
  4. Run the engine and bring the engine coolant temperature to normal operating range, approximately 88-96C (190-205F).
  5. Run the vehicle to full load and rated speed.
  6. Attach a manometer calibrated to read in inches of water, to the oil dipstick opening.
  7. Measure and record crankcase pressure.
  8. Shut down the engine.
  9. Remove the vehicle from the chassis dynamometer.
  10. Review the crankcase pressure test.
    1. If the crankcase pressure was greater than 1.50 kPa (6 in. H2 0), refer to section .
    2. If the crankcase pressure was less than 1.50 kPa (6 in. H2 0), perform a cylinder compression test.
  11. Compare the cylinder compression test results to specifications. Refer to section .
    1. If cylinder pressure is below specifications, refer to section .
    2. If cylinder pressure is within specifications, call Detroit Diesel Technical Service Group.

Worn or Damaged Valve or Cylinder Kit Repair

Perform the following steps for worn or damaged valves or a cylinder kit: ‪

  1. Remove the cylinder head; refer to section .
  2. Inspect the cylinder head for worn or damaged valves; refer to section .
  3. Inspect the cylinder kit components for worn or damaged liners; pistons or piston rings; refer to section .
  4. Verify repair to cylinder valve(s) or cylinder kit components; refer to section .
Test Engine with Repairs Made to Correct Worn or Damaged Valve or Cylinder Kit

Perform the following to determine if the repaired valve or cylinder kit has resolved the excessive crankcase pressure: ‪

  1. Start the engine.
  2. Run the engine and bring the engine coolant temperature to normal operating range, approximately 88-96C (190-205F).
  3. Run the vehicle to full load and rated speed.
  4. Visually inspect exhaust for excessive blue smoke.
    1. If the engine exhaust smoke emission appears normal for a rebuilt engine, no further troubleshooting is required. Shut down the engine.
    2. If the engine exhaust smoke emission is excessively blue, call the Detroit Diesel Technical ServiceGroup. Shut down the engine.