Positive Crankcase Ventilation: Testing and Inspection

INSPECTION/SERVICE

Checking Vacuum At The PCV Valve:

1. With engine idling, remove the PCV valve from cylinder head cover. If the valve is not plugged, a hissing noise will be heard as air passes through the valve. A strong vacuum should also be felt when a finger is placed over the valve inlet.

Checking Vacuum At Crankcase Filter Opening:

2. Install the PCV valve. Remove the crankcase inlet air filter. Hold a piece of stiff paper (parts tag) loosely over the opening of the cylinder head cover.

3. After allowing approximately one minute for crankcase pressure to reduce, the paper should be drawn against the opening in the cylinder head cover with noticeable force.

Inspecting PCV Valve:

4. Turn the engine off. Remove the PCV valve from cylinder head cover. The valve should rattle when shaken.

^ Replace the PCV valve and retest the system if it does not operate as described in the preceding tests. Do not attempt to clean the old PCV valve.

5. If paper is not held against opening in cylinder head cover after new valve is installed, replace PCV valve hose. The passage in the intake manifold must also be cleaned.

^ To clean the intake manifold fitting, turn a 1/4 inch drill (by hand) through the fitting to dislodge any solid particles. Blow out the fitting with shop air. If necessary, use a smaller drill to avoid removing any metal from the fitting.