You might try squirting some silicon spray into the bearing areas of the various pulleys. If the noise stops, that unit would be suspect. The water pump or alternator are likely units to be causing this.
Insert a socket or wrench on the spring-loaded serpentine belt tensioner then pull back; the belt will loosen.
Considering that the Buick Century has been in production on & off for nearly 70 years, adding a model year to your question might have been helpful. Assuming you're referring to the latest generation with the 3100 V6, a serpentine belt can be purchased online for less than $20. It would probably cost somewhat more at your local auto parts store.
I need to know if I need a special to to change my serpentine belt on a 2001 Buick Regal
Have vehicle scanned to determine the problem and have codes cleared
Buick Century was created in 1936.
I have used a socket with a ratchet handle. The ratchet will allow you to get more travel to move the pulley and get the belt off.
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There is no such thing as a 2005 Buick Century
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