C6.6 Engines For Caterpillar Built Machines Caterpillar

Probable Causes

• Misreading oil level

• Oil leaks

• Engine crankcase breather

• Oil level

• Air intake and exhaust system

• Turbocharger

• Low compression (cylinder pressure)

Recommended Actions

Misreading Oil Level

1. Accurately measure the consumption of oil and fuel over a period of 50 engine hours.

2. If the oil consumption is greater than 0.2% of the fuel consumption, use the following procedure in order to investigate the cause of the high oil consumption.

Oil Leaks

1. Check for evidence of oil leaks on the engine.

2. Rectify any oil leaks from the engine.

3. Check for evidence of oil in the coolant.

4. If no oil leaks are identified, refer to "Engine Crankcase Breather".

Engine Crankcase Breather

1. Check the engine crankcase breather for blockage or restrictions.

2. Check for excessive oil from the outlet of the breather.

3. Repair all defects. Verify that the repair has eliminated the problem.

4. If no faults are found, refer to "Oil Level".

Oil Level

1. Check the oil level in the engine.

2. If the oil level is high, check for contamination of the oil with coolant. Refer to Troubleshooting, "Coolant in Engine Oil".

3. If no contamination is identified, remove any excess oil.

4. If the oil level is satisfactory, refer to "Air Intake and Exhaust System".

Air Intake and Exhaust System

1. Check the air filter restriction indicator, if equipped.

2. Ensure that the air filter is clean and serviceable.

3. Check the air intake and the exhaust system for the following defects:

   • Blockages

   • Restrictions

   • Damage to the air intake and exhaust lines and hoses

4. Make all necessary repairs to the engine.

5. Ensure that the repairs have eliminated the diagnostic code.

6. If no faults are found, refer to "Turbocharger".

Turbocharger

Note: The turbocharger that is installed on this engine is a nonserviceable item. If any mechanical fault exists, except for the wastegate actuator, then the turbocharger must be replaced.

1. Check that the oil drain for the turbocharger is not blocked or restricted.

2. Check the turbocharger for evidence of internal oil leaks.

3. If necessary, replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".

4. Check that the repairs have eliminated the faults.

5. If the repairs have not eliminated the fault proceed to "Low Compression (cylinder pressure)".

Low Compression (cylinder pressure)

1. Perform a compression test. Refer to Testing and Adjusting, "Compression - Test ".

2. If low compression is noted on any cylinders, investigate the cause and rectify the cause.

   Possible causes of low compression are shown in the following list:

   • Loose blanking plugs in the cylinder head.

   • Faulty piston

   • Worn piston rings

   • Worn cylinder bores

   • Worn valves

   • Faulty cylinder head gasket

   • Damaged cylinder head

3. Perform all necessary repairs.

4. Ensure that the repairs have eliminated the faults.

5. If the fault is not eliminated, refer to the Troubleshooting Manual for your engine application.