^See if you can isolate it to the alternator then using the stethoscope method... Pelican I'm sure will honor a return/replacement.

Honestly I'm surprised the shop who did the replacement for you let it leave the shop that way. If there was no sound before installing the new alternator then there should be none after... first thing they should have done was check if the alternator was making the noise and informed you it's the problem, or could have spent another 10 minutes finding the problem for you.

Got a good chuckle out of that one!:thumbup:

I suggest some troubleshooting before ordering any more parts. When something wasn't there before you did the work and is there immediately after and since there are no coincidences, it is time to go back and check all the work and any new parts associated with that work. As has been mentioned, the most likely cause is the alternator but the best thing to do pinpoint the source of the sound before doing anything further.

UPDATE:

After all the suggestions here, I took the X5 to have it smoke tested and found that the Throttle Housing to Air Boot Elbow Rubber joint had a leak so I replaced that one but it still had the loud whine after. Took it to another BMW specialist and he said he can hear something behind where the pressure control valve is but didn't really like his diagnosis overall.

So I went ahead and decided I contact the parts store I got the alternator from and told them the issue and they told me that they will give me credit for the defective altnernator. So I went ahead and got a brand new Valeo alternator with the suggestion of Crystalworks and X53Jay4.8is and got it installed just this weekend and low and behold, the whining is totally gone. I can't for the life of me wonder why I waited this long to do that in the first place. You should have seen the big smile on my face as I was driving home from my indie mechanic's shop.

Thanks again guys for the great input as always.

PS: But, now I just have one noise that I have yet to figure out. Besides that whining which was already solved, I have a loud roar everytime I step on the gas first thing in the morning as if the engine is gasping for air or something. Same thing after work when the car has been parked for 8 hours, on my initial step of the gas, I can hear this loud noise again.

ANY IDEAS?

Is there a loss of power when that happens? Is the engine reving but the speed is not increasing normally?

clutch
 

I know you replaced it, but I bet it's your fan clutch. Especially since it is new. Would be valuable for you to take the main serpentine belt off for a start up and see what happens. You don't run it for more than 1 minute this way, but it would eliminate a lot of possibilities.

No, it picks up normally when I step on the gas. There's this part of a side street that I pull up in the morning to join a major highway and I normally have to speed up to match the flow of traffic and I gun it every time and it goes but it just has the loud roar from the engine bay.

I keep thinking its just an air leak somewhere. But then again, who am I to say.

Can't be the fan clutch because I replaced it 2 months ago while trying to figure out the whining noise which is already solved.

Have you replaced your main belt (or at least tried belt dressing on it)? I had a belt whine and I replaced a ton of stuff and on a whim tried belt dressing and the noise went away.

Do you hear the same roar when you rev the engine in park? And are you saying that once the engine warms up you no longer hear the roar?