Basicly the noise sounds like a supercharger whining..

Step on the gas it sounds louder.. I live in an apartment and I can hear it from like my window when my dad arives..

what can it be..?

I don't think it hurts the performance or anything just weird noise.. I know dam well I don't have a supercharger lol..

Most likely it's the power steering pump. The one on my '94 Deville was doing the same thing. I bought a rebuilt pump on eBay for around $30 and changed it out, and the supercharger whine is gone. It's easy to change, just rent a pulley puller/installer from an auto parts store.

Another thing, you posted this in the Northstar engine section. There's a forum right below this one for the 4.9 engines.

i suspect you meant to put this in the 4.9 forum

I agree, bad P/S pump

i suspect you meant to put this in the 4.9 forum

yup sorry new here.

thanks guys will change the ps pump.

yup sorry new here.

thanks guys will change the ps pump.

No problem! Post some pics of your Deville when you can. And let us know how the pump change goes.:thumbsup:

Before you go off changing things and spending loads of money, get a stetchscope for cars and listen to all the accessories that are belt driven.
I had an alternator bushing go bad and it made an awful whineing noise.
Another time I had a tensenor pully bearing go bad and the same noise.
You can also use a lenght of hose and touch the part with one end and put the other end to your ear. You can also use a stick for this.

If you have replaced the power steering pump would you share advice please?

I have a similar noise, I am starting off by just replacing the serpentine belt since its old and starting to crack. But someone mentioned my ps pump may be bad, it also started making noise on turns. Putting a screw driver on the ps fluid resovoir you could hear it better so thats what I am leaning too.

I figure ill check the pulleys while i have the belt off though.

AC could make noise as well.