STEP AS 5129043 - Caterpillar

Incorrect Engine Oil Level
Overfilling the crankcase will increase the consumption of engine oil. Make sure that the engine oil level is correct.When the engine crankcase is full, engine oil will be initially consumed at a relatively rapid rate. The rate of consumption is reduced as the engine oil level decreases. A crankcase that is always maintained at the full level will have a faster rate of consumption.If the engine has a system for automatically filling the crankcase with engine oil, check the level for the system. Adjust the system in order to provide engine oil to a level that is less than the full level. Make sure that the supply of engine oil is adequate.External Leak
Check for engine oil leaking from the seals at each end of the crankshaft. Look for engine oil leakage at the gasket for the engine oil pan and all lubrication system connections. Look for any engine oil leaking from the crankcase breather. This leakage can be caused by combustion gas leakage around the pistons. A dirty crankcase breather will cause high pressure in the crankcase. A dirty crankcase breather will cause the gaskets and the seals to leak.Measure the crankcase blowby according to the engine's Operation and Maintenance Manual, "Crankcase Blowby - Measure/Record".Internal Leak
There are several possible ways for engine oil to leak into the combustion chambers:
Leakage between worn valve guides and valve stems
Worn components or damaged components (pistons, piston rings, or dirty passages for engine oil)
Incorrect installation of the compression ring and/or the intermediate ring
Leakage past the seal rings in the turbocharger
Overfilling of the crankcase
Incorrect dipstick or guide tubeSigns of internal leaks include high consumption of engine oil, blue smoke, and excessive detonation.If the pistons are suspected, check the cylinder compression. Refer to the engine's Operation and Maintenance Manual, "Cylinder Pressure - Measure/Record".Worn Components
Excessively worn engine components and damaged engine components can result from the following conditions:
Contaminated engine oil
Incorrect fuel system settings
Contamination from the inlet airExtended Operation with Low Loads
Extended operation at low idle or extended operation at a reduced load will cause increased engine oil consumption and carbon buildup in the cylinders. This will occur if the engine is operated at a torque that is significantly below the rated power.The engine can be operated at a low load. However, engine operation at a low load is limited. For information on operation with a low load, refer to the engine's Operation and Maintenance Manual, "Engine Operation".