MBE 900 DDEC VI Troubleshooting – Section 8.1 Obstruction or Damage to Cylinder Head Cover Breather

Section 8.1
Obstruction or Damage to Cylinder Head Cover Breather

To determine if an obstructed or damaged breather is causing excessive crankcase pressure, perform a crankcase pressure test. Refer to "2.1 Crankcase Pressure Test" .‪

1. If the engine crankcase pressure is greater than 0.62 kPa (2.5 in. H₂ O), replace wire mesh element; refer to "8.1.2 Cylinder Head Cover Breather Resolution" .
2. If the crankcase pressure remained the same, check the air compressor; refer to "8.1.2.1 Test Engine with New Wire Mesh Element" .

Section 8.1.1
Crankcase Pressure Test

Perform the following steps to check the engine crankcase pressure:‪

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 the engine.
2. Run the engine and bring the engine coolant temperature to normal operating range, approximately 70-95°C (158-203°F).
3. Return engine to idle and remove the oil dipstick.
4. Attach a manometer calibrated to read pressure in kPa or inches of (H₂ O), to the oil dipstick opening.
5. Run the vehicle to full load and rated speed.
6. Measure and record crankcase pressure. Refer to "2.1 Crankcase Pressure Test" .
7. Shut down the engine.
8. Remove the manometer from the oil dipstick opening and install the dipstick.

Section 8.1.2
Cylinder Head Cover Breather Resolution

Perform the following steps to replace wire mesh element:‪

1. Remove the cylinder head cover; refer to MBE 900 Service Manual (6SE9007), engine chapter-cylinder head.
2. Remove the wire mesh element from the cylinder head cover.
3. Install a new wire mesh element to the cylinder head cover.
4. Install the cylinder head cover to the engine, refer to MBE 900 service manual, engine chapter-cylinder head cover.
5. Verify replacement of the wire mesh element; refer to "8.1.2.1 Test Engine with New Wire Mesh Element" .

Section 8.1.2.1
Test Engine with New Wire Mesh Element

Perform the following steps to determine if the new wire mesh element resolved the excessive crankcase pressure:‪

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 "2.1 Crankcase Pressure Test" .
   1. If the engine crankcase pressure is less than 0.62 kPa (2.5 in. H₂ O), no further troubleshooting is required. Shut down the engine.
   2. If the engine crankcase pressure is greater than 0.62 kPa (2.5 in. H₂ O), check the air compressor; refer to "8.2 Defective Air Compressor" . Shut down the engine.