Verify the oil consumption rate
Check the amount of oil added versus the mileage.
Lubricating oil leak (external)
Inspect the engine for external oil leaks. Tighten the capscrews, pipe plugs, and fittings. Replace gaskets, if necessary. Refer to Procedure 007-048.
Crankcase ventilation system is plugged
Check and clean the crankcase breather and vent tube. Refer to Procedure 003-011 and 003-018.
Lubricating oil does not meet specifications for operating conditions
Change the oil and filters. Refer to Procedure 007-037. See the corresponding Owners Manual or Operation and Maintenance Manual for the engine being serviced for oil specifications.
Lubricating oil drain interval is excessive
Verify the correct lubricating oil drain interval. Refer to the corresponding Owners Manual or Operation and Maintenance Manual for the engine being serviced.
Air compressor is pumping lubricating oil into the air system
Check the air lines for carbon buildup and lubricating oil. Refer to Procedure 012-003. If oil is found, see the Air Compressor Pumping Excess Lubricating Oil into the Air System troubleshooting
tree.
Lubricating oil cooler is leaking
Check the lubricating oil cooler for coolant leaks. Refer to the Coolant loss Internal troubleshooting symptom tree, if oil is found.
Lubricating oil level is above specification
Check the oil level. Verify the dipstick calibration and oil pan capacity. Fill the system to the specified level. Refer to Procedure 007-009.
Engine angularity during operation exceeds specification
Refer to the Engine Specification Data Sheet for angularity specifications for the engine being serviced.
Turbocharger oil seal is leaking
Check the turbocharger compressor and turbine seals. Refer to Procedure 010-033.
Piston rings are not seated correctly (after an engine rebuild or piston installation)
Check blow by. Refer to Section 14. If blowby is excessive, check the piston rings for correct seating. Refer to Procedure 001-043 and 001-047.
Lubricating oil is contaminated with coolant or fuel
Refer to the Lubricating Oil Contaminated symptom tree.
Valve stem clearance is excessive or the valve stem seals are damaged
Check the valve stems and seals. Refer to Procedure 002-004.
Cylinder head valve guides are excessively worn
Check the valve guides for wear. Replace the cylinder head if necessary. Refer to Procedure 002-004.
Piston or piston rings are worn or damaged
Check for air intake system leaks. Check the pistons and piston rings for wear or damage. Refer
to Procedures 010-024 and 001-047. Analyze the lubricating oil and oil filters to locate an area of
probable damage and cause. Refer to Procedure 007-048 and Procedure 007-083.
Internal engine damage
Analyze the oil and inspect the filters to locate an area of probable damage. Refer to Procedure
007-048 and Procedure 007-083.
