The AC idler pulley can fail causing a growling noise from the engine. A new idler pulley will be needed.Google+
Car Problem Reports
Honda Civic Replace AC Idler Pulley to Stop Growling Noise
Honda Civic Problem
Visitor, 1997 Honda Civic, 152,000 mi
Loud bearing noise especially noticed at high idle. I initially greased (white) bearing, but eventually will replace idler pulley.