Positive Crankcase Ventilation: Testing and Inspection

Fig. 10 Fixed Orifice Fitting And CCV System:

Before attempting diagnosis, be sure locations of fixed orifice fitting and air inlet fitting have not been inadvertently exchanged. The fixed orifice fitting is light grey in color and is located at rear of valve cover. The air inlet fitting is black in color and is located at front of valve cover.
1. Pull fixed orifice fitting from valve cover and leave tube attached.
2. Start engine and bring to idle speed.
3. If fitting is not plugged, a hissing noise will be heard as air passes through fitting orifice. Also, a strong vacuum should be felt with a finger placed at fitting inlet.
4. If vacuum is not present, remove fitting orifice fitting from tube. Start engine. If vacuum can now be felt, replace fixed orifice fitting. Do not attempt to clean plastic fitting.
5. If vacuum is still not felt at hose, check line/hose for kinks or for obstruction. If necessary, clean out intake manifold fitting at intake manifold. Do this by turning 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.
6. Return fixed orifice fitting to valve cover and leave tube attached.
7. Disconnect air inlet fitting and its attached hose at front of valve cover. Start engine and bring to idle speed. Hold a piece of stiff paper (such as a parts tag) loosely over the rubber grommet (opening) of the disconnected air inlet fitting.
8. The paper should be drawn against the rubber grommet with noticeable force. This will be after allowing approximately one minute for crankcase pressure to reduce.
9. If vacuum is not present, check breather hoses/ tubes/lines for obstructions or restrictions.
10. After testing, reconnect all system hoses/ tubes/lines.