High Pitched whine at cold start up. lasts about 30-45 seconds. Not affected by engine speed. After engine warmed up does not re-occur unless engine cools off say half hour or so. Seems to be located on front driver side. Did find info about replacement of the air emissions pump on a chev that seems to most look like it, but have not confirmed that it is characterized by a high pitched whine at startup as indicated above.
how to test emissions air pump and replace on 2001 Cadillac DeVille
by WIM4246 in Des Moines, IA on February 17, 2013
ANSWER by pushrod , February 17, 2013
Most likely drive belt//tensioner or driven componet, have your mechanic remove the belt to see if that makes it stop, may need to let him/her keep it a while.
ANSWER by globalhelper , February 18, 2013
agree with wetry