Grand Cherokee 4WD V8-4.7L (2003)
Positive Crankcase Ventilation Valve: Testing and Inspection
PCV VALVE/PCV SYSTEM
Fig. 21 PCV Valve/Oil Filler Tube - 4.7L V-8 Engine
1. Disconnect PCV line/hose by disconnecting rubber connecting hose at PCV valve fitting.
2. Remove PCV valve at oil filler tube by rotating PCV valve downward until locating tabs have been freed at cam lock. After tabs have cleared, pull
valve straight out from filler tube. To prevent damage to PCV valve locating tabs, valve must be pointed downward for removal. Do not force
valve from oil filler tube.
3. After valve is removed, check condition of valve O-ring. Also, PCV valve should rattle when shaken.
4. Reconnect PCV valve to its connecting line/ hose.
5. Start engine and bring to idle speed.
6. If valve is not plugged, a hissing noise will be heard as air passes through valve. Also, a strong vacuum should be felt with a finger placed at valve
inlet.
7. If vacuum is not felt at valve inlet, check line/ hose for kinks or for obstruction. If necessary, clean out intake manifold fitting at rear of 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.
8. Do not attempt to clean the old PCV valve.
9. Return PCV valve back to oil filler tube by placing valve locating tabs into cam lock. Press PCV valve in and rotate valve upward. A slight click
will be felt when tabs have engaged cam lock. Valve should be pointed towards rear of vehicle.
10. Connect PCV line/hose and connecting rubber hose to PCV valve.
