EXCAVATOR AR 1237675 - Caterpillar

Caterpillar Machines Equipped With Vane-Type Vickers Hydraulic Oil PumpsDuring cold weather, many machine operators start an engine and let it operate at low idle rpm to warm up before starting to work. Some times the operator will try to move the implement while the engine is still operating at low idle, but the implement does not move.
This is a normal condition when the oil is cold and thick. Because the engine rpm is low, the vanes in the hydraulic pump do not extend and there is no hydraulic oil flow.
After the engine oil pressure is acceptable, increase the engine rpm to approximately 1500 rpm. Operate the engine at this rpm for at least two minutes. This will extend the vanes and start the hydraulic oil flow.
Now the implement can be moved.