Combustion engines tend to generate a lot of gases, and they need to be removed from the engine in order to keep things running smoothly. The positive crankshaft ventilation (PCV) valve is designed to draw combustion byproducts and unburned fuel vapors from the engine's crankcase. It also serves to filter out the fuel vapors and return them to the intake valve to reduce unnecessary waste of gasoline.
Along with the gases being filtered through the PCV valve, there are also traces of oil, moisture and grease that can build up and cause problems. A clogged valve can lead to reduced fuel efficiency, and if it is unable to open properly, it can also damage the engine. This is why it is important to clean the valve regularly.
The PCV valve is typically located next to the valve covers on top of the engine block, but this can vary between different makes and models. The owner's manual can help you locate the specific location for your vehicle. A PCV valve is a metal cylinder that is about two inches long and covered with a rubber hose.
When removing a PCV valve for cleaning, it is important to make sure that the car has been off long enough that the engine has a chance to cool down. Once you are sure that the engine is cool, remove the rubber hose from the valve. Then, clamp a pair of pliers around the valve and pull straight up to remove if from the engine. There should be an o-ring between the valve and the engine block to create a seal between the two. Either leave it on the engine or put it somewhere safe while cleaning the valve.
To clean the PCV valve, you should use compressed air to blow out any loose debris that may have built up inside it. Then you will need to coat the valve, inside and out, with an engine degreaser. Just to be sure, use compressed air in the center cavity of the valve once more before replacing it.
If you removed it, replace the o-ring before putting the PCV valve back in place. Make sure that it is flush with the valve and the engine so there are no leaks. Then reconnect the hose and you're done.