I bought a new PCV Valve for my 97 Dodge Caravan 2.4L but I am unable to locate in the engine where the old one is.

Is it really recommended to replace this every now and then?

It really doesn't need it that often if you change oil and filter regularly. I have no clue where it is in 2.4's, but it's gotta be in the intake system somewhere......

Well i can tell you on my 97 with a 3.3 the pcv valve is located just to the left of the throttle body right below the plenum. It has a rubber connection near the throttle body and the hose run to the valve cover. I hope this helps. Look on the valve covers for it or a hose from the valve cover to the intake. I hope this helps.