VW Repairs: Positive Crankcase Ventilation (PCV) System

PCV Valve Operation | German Car Depot

Volkswagen engines contain a Positive Crankcase Ventilation (PCV) system that allows for the controlled release of blow-by from the motor. Blow-by is the excess gas that gets past the piston rings into the crank case. To prevent too much pressure from building up inside the crank case, the PCV vents these emissions. This technology was originally introduced to tanks in World War II, so that water couldn’t get into the crank case when the tanks were fording rivers and streams. In the 1950s, it was discovered that venting this pressure into the atmosphere was a likely cause of smog in urban areas. Using this PCV system on internal combustion engines prevents these gasses from being directly vented into the air.

If you have noticed that your engine is leaking oil, it may be a sign that there is a problem with the Positive Crankcase Ventilation system. If a PCV valve has become plugged, then pressure will begin to build up and oil seals and gaskets may begin to fail. Also, when the engine is being prevented from venting properly, air cannot flow from the crankcase which will then cause a buildup of engine sludge.

If you have noticed any oily deposits on the air filter or in the air filter housing of your VW engine, this is a sign of pressure building up in the crankcase. A bad PCV valve will also cause excessive oil to be consumed by the engine and will result in oil leakage. If any of these things are occurring with your car, you will likely observe a decrease in your VW’s performance. The engine may begin stalling out with increasing frequency. You will probably also begin noticing oil leaks on the ground after your vehicle has been parked.

Signs of trouble:

  • Oil in the air filter
  • Oil leaking from seals and gaskets
  • Stalling and decreased engine performance

Other causes of oil leaks could be a loose or broken oil drain plug. If the threads are worn out on the plug, or if they aren’t aligned properly, this can cause oil to leak. Also, the oil filler cap by be loose, broken or even missing which would cause oil to spill out while the engine is on.

While some oil leakage is pretty common over the lifetime of an automobile, it is certainly not something that is unique to Volkswagens. However, failure to fix this problem will result in the continual deterioration of the engine. You vehicle’s performance will suffer and the longer you wait to address the problem the more expensive it will be to fix.

To fix the problem with a PCV system, a mechanic may need to replace the PCV valve as well as the PCV hose and any seals and gaskets that may have become compromised. PCV valves generally last for up to 80,000 miles but may need to be replaced sooner.

If you are the owner of a Volkswagen and are experiencing any of the issues with the Positive Crankcase Ventilation (PCV) system outlined above, then you should bring your vehicle into the German Car Depot in Hollywood, FL. The German Car Depot is a trusted, independently run VW garage that offers inexpensive repair solutions as compared to the dealerships. Visit us today for an honest estimate and quality service.

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