on top of the valve cover
No, the crankcase ventilation systems employed on diesels are not PCV (Positive Crankcase Ventilation) systems. They are CCV (Closed Crankcase Ventilation) systems. Diesels do not produce sufficient vacuum for a PCV system. They use only a crankcase breather which is vented to the filtered side of the intake ducting. The engine can "breathe" both in and out via the breather cap. The round black thing on the TDI valve cover is a breather cap.
The PCV or positive crankcase ventlation valve does as it is named. It will remove harmful gases from the engine. Also, you can find breather caps on the valve covers, this also helps to remove and fumes from the crankcase or engine base.
If White smoke with oil come out from DDC running Engine Breather out let, it symptoms of Piston Ring set wear out and injector has to be calibrated,
Oil may squirt from the breather of your Yanmar 4LH-DTE diesel engine at high RPM due to excessive crankcase pressure. This can be caused by worn piston rings, a clogged breather system, or insufficient oil viscosity, leading to blow-by and forcing oil out of the breather. It's essential to check for these issues, as they can indicate underlying engine problems that need addressing to prevent further damage. Regular maintenance and monitoring can help prevent this situation.
To clean a crankcase breather on a small engine, first, ensure the engine is cool and disconnect the spark plug for safety. Remove the breather from the engine, then clean it using a solvent or carburetor cleaner to remove any oil sludge or debris. Rinse it with clean water, allow it to dry completely, and reassemble it back into the engine. Finally, reconnect the spark plug and start the engine to ensure proper operation.
Engine is severely worn.
The engine is getting worn and blow by is getting into the crankcase and forcing oil from the valve cover into the air breather.
The breather tube on a Tecumseh 5 hp engine may spit oil due to excessive crankcase pressure, which can be caused by worn piston rings or a damaged cylinder. This pressure forces oil out of the breather, leading to oil spitting. Additionally, overfilling the crankcase with oil can exacerbate this issue, causing oil to be pushed through the breather. Regular maintenance and proper oil levels can help mitigate this problem.
The crankcase breather system typically consists of several key components: the breather valve, which allows gases to escape from the crankcase; a filter or separator that removes oil mist from the escaping gases; and tubing or hoses that connect these components to the engine intake system. This system helps to prevent pressure buildup in the crankcase and reduces emissions by redirecting the gases back into the combustion process. Additionally, some systems may include a PCV (Positive Crankcase Ventilation) valve to regulate airflow and further enhance efficiency.
Detroit diesel, Cummings, Deutz
the valves or rings are allowing compression blow by to enter the crankcase which causes excess pressure that is brought to the carburetor by the breather tube. your engine is getting tired or you have too much oil in the crankcase.
The engine should have a crankcase breather tube connected between the valve cover and the air cleaner. With the crankcase breather removed and a non-vented cap installed on the valve cover in its place, the PCV would create the vacuum you have.