I had a similar problem with my 2004 kia optima, I took it back and forth
to the dealer numerous times, and it would squeal all the way there and
STOP as i was driving onto the lot.  I left it overnight, and they started
it up the next morning, now it squealed.  The tension was within specs
according to the mechanic, but still needed to be tightned a little bit.  
Now i have no problems at all.