I got the mounting hardware for the idler pulley from a forum member, can't think of his name, I had my own pulley and I just thought it was a good idea. My belt never squealed in the 1st place but the idler sure makes changing a belt a lot easier along the road.
Ironically that's exactly what happen to me a week ago. Temp needle went high and light came on within sight of a NAPA store. Took old belt with number on it to the counter and bought new belt and a ratchet. Took an hour to put it on since the motor was hot. A cold motor would have been 5 minutes.
Bottom line no squeal before or after.
"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut