The idler pulley for the serpentine belt can fail causing noise from the belt area. Our technicians report the pulley has been known to fail completely which can cause the belt to break or be thrown off.Google+
Car Problem Reports
Saab 9-5 Noise from Idler Pulley
Saab 9-5 Problem
Engines Affected: 2.3L 4 Cylinder Turbo, 3.0L V6 Turbo, V6
Average Mileage: 100,155 mi (61,000 mi - 123,741 mi)
out of the blue a noise began under the hood at start up and when idiling. Found it was the idler pulley.. Get it checked as it can snap off w/o warning.
Same thing happened on my 9-3, Had the pulley and belt replaced, I spent about $150.00 parts and labor. Now I'm repeating the process with my 9-5.
Visitor, 2000 Saab 9-5, 3.0L V6 Turbo, 105,500 mi
Idler Pulley squeaking, put WD-40 on it which did make it stop squeaking, but I fear the bearings are going to lock up and break the belt. Part is $50-$75 with it costing about 1 hour labor to put it in or do it yourself.
Last few days on cold start engine idles very rough up and down between 1k-3k rpm then dies, second start idles rough for a seconds then idles / drives normally.
Visitor, 1999 Saab 9-5, 2.3L 4 Cylinder Turbo, 90,000 mi
Don't wait.... I waited and paid
Visitor, 2000 Saab 9-5, V6, 100,000 mi
Loud screeching noise now loud ticking noise coming from under the cover where the timing belt pulley is. Going in to the shop Monday. Uggg!
Idler pulley started making noise, especially when cold. I made an appointment to have my mechanic fix it but it broke. Now I will fix it myself this weekend.