Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Positive Crankcase Ventilation: Testing and Inspection

Fig.9 PVC Test-Typical:






WARNING: Apply parking brake and/or block wheels before performing any test or adjustment with the engine operating.

With the engine idling, remove the PCV valve from its attaching point. If the valve is operating properly, a hissing noise will be heard and a strong vacuum felt when placing a finger over the valve inlet (Fig. 9).

With the engine off, shake the valve. The valve should rattle when shaken. Replace the valve if it does not operate properly. Do not attempt to clean the PCV valve.