Where is the PCV valve? I've searched here and looked under the hood. I have a 99 D2

 

There is not one, in the way you are thinking. Download the RAVE and read through it. It will enlighten you on many things about your Disco2. Savana Buzz has links in his signature to the download.

 

On page 267 of 1529 in the shop manual it shows parts location and tells you how it works, similar to D1. They call it crankcase emisison control. In the old days you had a breather cap with some steel wool inside it as a filter.