A spool failure is one of the reasons for the unstable operation of the engine at idle, a decrease in idle speed, and oil leakage.
Typical crankcase ventilation scheme: 1. Suction manifold; 2. Breather; 3. Hose; 4. Spool; 5. Inside crankcase gases; 6. Air
Examination
1. With the engine running, pinch the hose between the spool and manifold. In this case, characteristic clicks should be heard.
2. If clicks are not heard, then stop the engine, remove the spool (see Chap. 1) and shake. If there are no clicks, then replace the spool.
3. Check the condition of the system hoses. Replace damaged or clogged hoses.