Don't go by appearance, all used PCV valves look dirty. There are two simple ways of checking it:
1. Remove the PCV valve from its grommet. With the engine off, shake the valve. If it’s good, you’ll hear a solid clicking sound.
2. Or, check it in place with the engine running. Pull the PCV valve from its housing and place your thumb over the PCV valve opening. You should feel it click. If the click sounds or feels mushy, replace the valve.
For what they cost, it's rarely worth cleaning them.
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Don't go by appearance, all used PCV valves look dirty. There are two simple ways of checking it:
1. Remove the PCV valve from its grommet. With the engine off, shake the valve. If it’s good, you’ll hear a solid clicking sound.
2. Or, check it in place with the engine running. Pull the PCV valve from its housing and place your thumb over the PCV valve opening. You should feel it click. If the click sounds or feels mushy, replace the valve.
For what they cost, it's rarely worth cleaning them.
remove it and shake the PCV. if no rattle sound. dirty,
clean it with car & choke cleaner spray, then when rattling sound appears after cleaning, reinstall back
engine will not idle smooth if pcv is clogged
u don't.... u just replace them every 30k miles or so........they cost under 5 bucks at any parts store.....