1. Carefully clear all details of the oil pump and check their condition.
2. Check a condition of the piston of a safety valve and a spring. In the presence of wear or damages it is necessary to replace the piston and a spring in a set.
3. Using an edge щупа, check a gap between teeths of an internal and external rotor...
4.... and also between an external rotor and the case of the oil pump.