2009 rogue question about oil loss

[wehrmachtoberst]

Hello everyone! New to the forum with a question: I own a 09 Rogue. I recently went to a Ken Towerys to have some stuff done. Oil change, new belt etc. before I went I was not burning oil at all. I am is burning like a quart every 2-3 weeks. I have been told that I should start with the pcv valve. I have looked high and low on here and can't find any info on where it is. Where is it located? Also why am I burning so much oil all of a sudden? Have had the car 2 yrs with no problems until after I took it to this place. 76,000 miles on it now. And it does smoke BUT only when I first start it. Nothing after that. And yeah it had some sludge when thy changed it.

I'm beginning to wonder if they messed it up a bit. Again no problems before I took it there. Any thoughts? I did put in some Risilone to combat the sludge. Thanks in advance
Paul