ROD AS 3625304 - Caterpillar

EnginesIf your customers tell you that the above engines use too much oil, your first troubleshooting step is to make sure that the oil consumption is excessive (too much). To do this, use the Oil Consumption Report, Form No. 01-883-81227-3. An analysis of this completed form will tell you if the engine's oil consumption is excessive.
When it is necessary to disassemble the engine, remember that there are several factors that can cause excessive oil consumption. Check the piston compression rings for excessive end gap and the cylinder bores for wear. See the Service Manual for methods and specifications to measure the wear. If the rings or cylinder bores are worn, there was dirt in the inlet air to the engine.
One other reason for excessive oil consumption can be flaking (small pieces broken off) of the Molybdenum face material on the compression ring. This flaking can be caused by a defect in the bond of the face material to the ring. Check the flaked rings. If they are not worn more than the specifications given in the Service Manual, bond failure is the cause. If the rings are too worn, dirt is the cause.