Are you sure of location? Our 2006 last summer made a similar sound, would go away once warmed up. Then eventually it did not go away. It was a bearing in the alternator. It was really loud weird noise, hard to locate.... then would go way once warmed up so it was really hard to track down.

 

Seattle, WA

That would make more sense since when increasing rpm on start it almost flutters through and then stops. Like towards end of the video did yours also make that noise on throttle? Did you replace the whole alternator to make it stop or just let it fix itself.

I want to iron this our since I have a stage 1 tune waiting.

 

Pretty sure it's a leaking exhaust manifold. Pull the turbo heat shield and you'll see the black soot accumulating near the leak. This usually happens when the studs/nuts back out (best case scenario) or the studs break, allowing the exhaust gasses to burn the gasket. When fixing this, make sure the orientation of the thick washers on each stud have the "UT" (convex part) towards the turbo and not the engine. They act like a spring:

 

I was under the impression that the exhaust leak would be like rumbling and not a high pitch almost closer to PCV sound. Is it not the case on these models?
Would getting to it be the same way as with the turbo back exhaust or even further up?

 

I'm 98% sure it has something to do with the exhaust manifold: gasket bad, broken studs, backed off nuts.

I recently removed my engine and there were loose nuts again and some studs had lost their nuts completely, no broken studs as they were replaced.

I won't link the million part series I had on my v50 as it was not too intense throughout its progression, and got better with some tightenings. (Plus my car had already had this job done documented at a shop before I bought it)

I will link this v50 I took a look at a while ago , and you can compare sounds. if you watch the whole video you will hear it on start up, but to hear pitch that matches yours, just skip to 2:55- 3:15

Edit: listen to the startup at 2:05 too, also at 3:30 when I give it gas and at 6:00 the short bit of driving is what it sounds like when its starting to get bad the squeal

 

Yes it is exactly like that especially the drive. How long did it take you to fix this?

 

It appears to be the exhaust manifold related. Anyone know the part numbers for the studs and nuts? Especially since this is the revision b7 engine not the b3, I hope that doesnt cause any issues with the size since I know that the revision was related to the turbo mounting.


Looking around forums how to do this job now.

 

I was under the impression that the exhaust leak would be like rumbling and not a high pitch almost closer to PCV sound. Is it not the case on these models?
Would getting to it be the same way as with the turbo back exhaust or even further up?

I'm pretty sure the cause of the high pitch is the MLS steel exhaust gasket fluttering when there is high exhaust pressure (during the cold start high idle and accelerating)

T3 and T7 engines are mechanically exactly the same, FCP has the both studs and nuts (these need to be flange oval lock nuts) 12 qty of each.

Studs: P/N: 982667
Nuts: P/N: 985868 (Although these work exactly the same for a fraction of the price)

Job will basically removing all coolant and oil lines from turbo, then disconnecting turbo from cylinder head, push it back and then clean, replace what's necessary (gasket, studs, nuts,etc) and put back together. There isn't that much room between engine and firewall. So pulling the downpipe and turbo wouldn't be a crazy idea.

 

Thanks for the part numbers. The more I read on this the more it seems like an all day job. A good thread I found for those with same issue is this one:

https://www.swedespeed.com/threads/exhaust-manifold-gasket-and-stud-replacement.663590/#replies