My stock turbo sounds like a old police siren on cold start. Only started do this when I changed the oil. Dip stick reading is correct for amount of oil in motor. Any ideas anyone?
After you get the orange elbow off, look at the inlet with an inspection mirror. If you can see rub marks on the inside of the compressor housing, that's the source of your noise. A few years ago, a member on here had the band that holds the compressor housing to the center section rust in two causing the wheel to rub. If you catch it soon enough, you can save the turbo.
We can rebuild your turbo, if the stock wheel is still intact for $250. We can also upgrade your stock turbo with our billet wheel, and full rebuild for $650. Bolt on. More efficiency, faster spool up. HTH