After having done this myself and seeing everything inside the belt housing, I'm beginning to wonder what all this talk about replacing the auto tensioner is. Like I said, the auto tensioner is just a spring loaded piston that keeps constant pressure on the tension pulleys. Now, my car had this grrrring noise before I had this done, and now it doesn't...... he filled the tensioner with plenty of oil, and the factory belts themselves looked worn, but other than that, there was no changes. No grrrring now. I'm beginning to question the validity of the auto tensioner replacement. Seems like a waste of money. Again, what I have learned by doing it myself is priceless.