How to test PCV valve and clean it

PCV valve, which stands for Positive Crankcase Ventilation, functions to flow air from the crankcase to the intake manifold according to the intake manifold's air requirements. Yes, this PCV valve is located on the engine cylinder head cover and connected to the intake manifold by a hose.

PCV Valve is used to suppress and reduce the amount of blow-by gas generated in the engine due to incomplete combustion, especially Hydro Carbon (HC). Therefore, the crankcase air flows back into the intake manifold for the re-burning process in the engine.

This flowing air stream generally contains oil vapour and residual gas from combustion. The PCV valve will gradually become clogged with dirt carried along with oil steam as time goes by.

The residual and deposits can cause engine problems. The engine is difficult to start, and the engine idle speed does not match. Inspection and cleaning of the PCV valve also need to be done to anticipate those engine problems. Check the PCV testing and cleaning info below

How to test PCV valve

Open the hood and note the location of the PCV valve on the cylinder head cover.
Remove the PCV valve from the cylinder head cover and leave the vacuum hose attached to the PCV valve.
Turn on the engine and leave it until it reaches the idling rpm position.
Close with a finger right at the PCV valve's open end to check for air vacuum from the intake manifold. Feel the air straw on your finger. If you don't feel a vacuum, the PCV valve may be blocked and clogged.
Turn off the engine after the vacuum check and remove the vacuum hose attached to the PCV valve.
Shake the PCV valve, then listen for a check needle sound inside the valve. If you don't hear a crackling sound, the valve in the PCV valve is clogged or blocked.

PCV Valve conditions that are considered good and can function are as follows

There is an air vacuum that occurs when doing the vacuum test.
There was a crackling sound when the PCV valve shook by hand.

If tested with these two conditions, the PCV valve does not indicate what it should be; the next step is to clean the PCV valve.

Also read:

What does a PCV valve do?

How to clean PCV valve

Spray the penetrant liquid to clean the dirt in the PCV Valve, such as "Carbon Cleaner" penetrant. Close the PCV valve hole and try to shake it again. Do repeated spraying until the liquid that comes out looks clean and the valve inside the PCV valve can move.

After cleaning, plug it back in and do PCV testing to ensure that the PCV valve inspection and cleaning process has been done correctly. However, after cleaning and do PCV testing, the valve inside the PCV still doesn't feel moving; you should replace the PCV valve with the new one.