Welcome to the Nissan Patrol forum. To post a question and to see less adds on the forum then you will have to register
first. We are an easy going friendly forum so join in the conversations and feel free to ask any questions.
Become a forum sponsor for only $20 and see no adds with faster page loading times and many extras benefits.
I had this exact sound in my Patrol maybe five, six years ago. I can't remember what the cause was. I do remember changing out the a/c idler bearing on the pump though. Could be this.
Take the belt off the a/c pump and see if the noise is still there. Atleast you can rule out the a/c if the noise still remains.