Should the PVC valve on your 99 jeep grand Cherokee 4.7 make noise?

The PCV (Positive Crankcase Ventilation) valve on a 1999 Jeep Grand Cherokee 4.7 should operate quietly under normal conditions. If you hear noise, such as a rattling or hissing sound, it could indicate a malfunction or blockage within the valve. It's important to inspect the PCV valve and the associated hoses for any issues, as a faulty valve can lead to engine performance problems. If in doubt, consider having it checked by a professional mechanic.