Engine whistling when cold in morning

Not sure the significance of the cold part. Typically when I hear a vehicle whistling, if it's under the hood, I always suspect a vacuum leak. A late model vehicle like that should throw a check engine light and some trouble codes if it were a vacuum leak.

may be you should make a diagnostic and you can do it in a garage or you can do it by yourself if you want to do it by yourself you need some tools and you can find some good ones here: diyobd2.fr

You are so right the IAC can make that whistling sound,

you most likely have a loose belt.only a mechanic can tell you which one. this is an issue that needs to be dealt with,or else you can be in a break down situation. the whistling is a belt slipping,then when it warms up,it quits right? you never hear it unless it's a first start up,or a cold engine start.as long as engines warm it will restart with no sound at all. please get an estimate at least 2 estimates,it should not be very expensive,less than$60.00 and thats high. thank you for choosing fixya.com

well it may help if you open the hood, then start the car and see if that helps you locate the item which is whistling. many cars have a power steering pump which likes to whistle until it gets warm. generally this is less than 5 minutes, and that is more like a screeching sound. something is either blowing out or sucking in through a small orifice to make the whistle, you need to physically locate the source of the sound. many bearings are in there spinning and any of them can be doing a cold screech.

myself I have been know to use a BFS, which is a big long screwdriver, i touch the pointy end to each of the spinning components and put the handle end to an ear. yes this process is not suggested for people with long hair or just no damn sense. but as i move the pointy end from component to component i know immediately when i touch it to the screechy one.

it could be a pulley that is cold or lubricant on it is low. Or could be the air intake system. Nothing serous anyways.

you may have a tensioner or idler pulley starting to go bad. They make a high pitched whistle when the bearings are on thier way.

Simply have someone slowly bring it up to 2000 rpm and listen with the end of a wooden broom handle touching the center bolt on each. Be careful not to get caught.

If you're not used to this you may be able to hear it whithout use of the "hearing aid"

Your drive belt may simply need dressing. You can buy this at almost any auto parts store for about 4 bucks. (dont use anthing else as you will cause the belt to stretch creating more issues)

might be an AC compresser thats bust

its proberly what they call a secondary air intake pump - what this does is increase the air flow only on cold start up - the colder it is the longer it stays on - if the noise gets louder and you will notice - get it changed - we have the same problem over here on the vauxhall omega and corsa's - bless em got to be GM

Actually - I had the same problem and replaced my brakes 4 times in a year. YES 4 TIMES because of the whistling. I switched from metallic to ceramic pads and works like a charm! Ceramic will not allow the noise, plus I have found to have much better control over braking and short distances.