C15 and C18 Engines for Caterpillar Built Machines Caterpillar

Oil Consumption Is Excessive

Usage:

D9T NJH

Probable Causes

Incorrect oil level in the crankcase
Oil leaks on the outside of the engine
Oil leaks in the combustion area of the cylinders
Oil leakage at the injector
Incorrect oil viscosity
Condition of turbocharger

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

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Table 1
Troubleshooting Test Steps	Values	Results
1. Excessive Oil in the Crankcase A. Check the engine oil level. Too much oil in the engine crankcase can cause the engine to consume oil. B. Ensure that the dipstick is properly calibrated and/or that the dipstick is correct for the application. Calibrate the dipstick and/or replace the dipstick. Refer to Systems Operation/Testing and Adjusting, "Lubrication System" for calibration of the dipstick gauge.	Oil level	Result: The oil level is correct. Proceed to Test Step 2. Result: The oil level is high. Remove excessive engine oil from the crankcase. Verify the repair.
2. Oil Leaks on the Outside of the Engine A. Check for oil leaks on the outside of the engine. Refer to Systems Operation/Testing and Adjusting, "Lubrication System".	Oil leaks	Result: There are oil leaks on the outside of the engine. Find the source of the oil leaks and make the necessary repairs. Result: There are no oil leaks on the outside of the engine. Proceed to Test Step 3.
3. Oil Leaks in the Combustion Area of the Cylinder A. Check for oil leaks in the combustion area of the cylinders. B. Check for excessive engine blowby. Excessive engine blowby will cause unnecessary oil consumption. Excessive engine blowby can also cause unnecessary engine wear.	Oil leaks	Result: There are oil leaks in the combustion area of the cylinder. Make the necessary repairs. Replace parts, if necessary. Result: There are no oil leaks in the combustion area of the cylinder. Proceed to Test Step 4.
4. Oil Leakage At the Injector A. Check for the excessive transfer of oil from the high-pressure oil supply in the injector to the fuel return in the cylinder head.	Oil leakage	Result: There is oil leakage at the injector. Make the necessary repairs. Replace parts, if necessary. There is not oil leakage at the injector. Proceed to Test Step 5.
5. Oil Viscosity A. Excessive consumption of engine oil can also result if engine oil with the wrong viscosity is used. Engine oil with a thin viscosity can be caused by fuel leakage into the crankcase or by increased engine temperature. Refer to the Operation and Maintenance Manual for additional information.	Viscosity	Result: The engine oil viscosity is correct. Proceed to Test Step 6. Result: The engine oil viscosity is not correct. Replace the engine oil, Refer to the Operation and Maintenance Manual for additional information.
6. Condition of Turbocharger A. Check the turbocharger for leakage.	Turbocharger	Result: The turbocharger has leakage. Make the necessary repairs. Replace parts, if necessary.

Complete the procedure in the order in which the steps are listed.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).