Hi Guys

Just a quick question. I have a 2001 Deville with the Northstar. This morning, when i started her up, there was a strange noise. The engine was cold and its starting to get alittle chilly here in Ontario, so this might be normal. The engine starts up fine, but then there is this whirring sound. Almost sounds like some sort of hydraulic motor lifting or spinning or somthing like that. After about 10 seconds or so it whirrs lower and lower and eventually stops with a sound like when you turn on your accessorys before the starting of the engine and the fuel is brought up to your engine. It is strange and while not super loud it is noticable. I just bought this car and I hope its somthing normal. Any thoughts or idea will be greatly appreciated. Thanks.

See the small square grill to the left of your steering column? That is where the asperator is located. There is a small fan in there that draws cabin air over the sensor so the system knows whether to heat or coll to reach the requested tempurature. Those fans are known to get noisy when cold. Put an ear to that grill and see if it is coming from there.

I am pretty sure the noise is comming from the engine bay, not the cabin, but I will check that out Ranger. Thank you for the response. I was expecting more responses from all you Caddy people out there. I bought a Factory GM warrenty with the car but I don't want to use it already.

That Whirring noise or Hydraulic sound is really strange. I don't know quite how to put it, but the sound sounds like it is somthing going on in the engine bay that is supposed to be happening. Its just somewhat loud and kind of embarrasing. Thanks again, hope to hear from more people soon.

Air compressor for the suspension?

Mine (99) makes a similar sound. May last 10 minutes or more. It sounds like a hi-pressure hydraulic pump. Not real loud, infact unless you roll down the window you can't usually notice it. With all the gizmos on these cars if you worry about every little sound (especially after they have some miles) you will go nuts.:alchi:

You have a warrenty to cover anythng major, so I would just keep listening and see if it gets worse....

Hard to say. You'll have to get under the hood and do some snooping around. Could be a belt tensioner, idler bearing or alternator bearing. Maybe P/S pump low on fluid.

Thanks for all the feedback guys. I'm gonna post some pictures of my baby soon.

As for that strange, strange sound, I think I'm gonna take it back to the dealership and have those guys take a look. The only downside is the fact that it only makes the sound after sitting for a while, so maybe I'll go check out the new DTS while I wait.

If you guys have any more ideas or if anyone else reads this, please please share any advice or if any of you have gone through the same thing as I have, with a 2000+ Northstar

Thanks again guys.

Sal - Did you ever find out what that noise was? Mine has been doing it in the morning (been getting colder out in the am); it seems like it stops as soon as the idle kicks down. Sounds like a jet engine warming up, or the whine of a supercharger.

My current guess is that it's the Secondary Air Injection Pump. Does that make sense to anyone here? I just wish it would have started doing this two weeks ago, when I had it into the dealer for something else...