What does the Positive Crankcase Ventilation PCV valve do?

Inside a combustion engine, many tiny explosions take place in order to release the fuel’s energy and power your car. This combustion process produces toxic and harmful gasses which can find their way into the crankcase, which is the protective cover for the crankshaft. If these gases remain in the crankcase, it can cause serious engine problems. 

The purpose of the positive crankcase ventilation (PCV) system is to remove this gas from the crankcase, sending it through the PCV valve where it is pumped back into the engine cylinders for another chance at combustion. 

The PCV valve also helps to keep your engine free of moisture due to the constant air circulation it provides. This allows for an improvement in engine health and oil cleanliness. The PCV system also improves fuel economy by reintroducing unburnt fuel to your engines cylinders.

If the PCV valve fails, the following problems can occur:

  • The engine crankcase pressure increases.
  • Oil leaks can occur.
  • The engine will be subject to increased wear, reducing its lifespan.
  • Moisture and sludge can build up in the engine.
  • The engine will lose power and not work correctly.
  • You may have extra smoke out of your exhaust pipe
  • You may have a lean air / fuel mixture due to an air leak

Learn more about the PCV valve >


Common causes of faulty PCV valve:

A positive crankcase ventilation valve can fail if any of the following problems occur:

  • The valve becomes stuck open, letting too much air through.
  • The oil seals fail, causing oil to leak.
  • The valve becomes stuck shut, preventing air from going through.


Symptoms of a faulty PCV valve

Engine oil leaks – A faulty PCV valve can lead to oil leaking from your engine. Oil leaks should be repaired as soon as possible. This is because a lack of oil can significantly increase engine wear, resulting in expensive damage.

Lean air/fuel mixture – A lean mixture occurs when too much air is entering your engine. If the PCV valve becomes stuck open, too much air will enter the combustion chamber, resulting in decreased engine performance.

Check engine light – A faulty PCV valve may cause the check engine light to turn on. This often happens when the engine sensors detect too much air.

Misfiring engine – A misfiring engine is more likely to occur with a faulty PCV valve, especially when idling.


Positive Crankcase Ventilation (PCV) Replacement in Hamilton

Is your positive crankcase ventilation valve – PCV valve system in need of replacement? If so, we can help!

At Grimmer Motors, our skilled, qualified mechanics can effectively diagnose problems in the PCV valve system and provide high-quality valve replacements that will last the test of time. 

For all PCV valve diagnostics and services in Hamilton, contact Grimmer Motors today!


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