My 99 Deville Concours has developed a humming sound through the steering wheel on sweeping left handers. It doesn't make any noise when turning the wheel left stopped and at low speeds. From about 35 it is noticeable and it gets louder up to 55. As the speed increases above 55 it seems to get less loud but other noises (not really that much in this car) may just be covering it up. Straight ahead and to the right it is silent. As the driver it is most noticeable through the steering wheel but my kids have commented on it sitting in the passenger seat. Anybody got any idea what is going on? It started 6-8 months and 15-20Kmiles ago. The power steering reserviour is full and doesn't seem to be going down.

chuck
99 Deville Concours

 

Check for power steering hoses contacting each other or the frame. I think you are feeling power steering fluid being pumped thru the hoses