had a loud screech from engine. Car was running just fine.
Luckily I was home when I discovered it. The idler completely melted but the tensioner was still applying tension and there was zero damage to the serpentine belt.
$20 autozone pulley, 5 minute fix
You are lucky that happened to mine at 60mph all of the warning lights came on and I pulled over. Looked at the engine and turned it off as temp was rising quickly. AAA towed me to the autozone where I found the part also. Put new pulley and had a spare belt, BUT later on I had my new alternator bearing go out, and my fan viscous thing was slightly bent. For anyone who can see there fan is not perfectly spinning, it will cause failure of the water pump. All good now.