2006 Jetta BRM squeal coming from engine.

I have noticed a squeal coming from my TDI. If I rev the engine quickly it will squeal almost every time. The squeal on happens for a second or so and then goes away and it is always at the same rpm. I also notice it when turning with the engine accelerating at the same time. I suspect that it is belt related but I can't seem to find it. I had my wife rev the engine and it is difficult to pinpoint where it is coming from.

Any ideas to diagnose or what is typical to squeal on this motor?

Usually a squeal like that is related to a pulley or tensioner. It may not be the most scientific method that a rocket surgeon would use, but I had good luck pinning pointing a squeal by giving a light spray of lubricant on each pulley and tensioner one at a time and go for a quick ride after trying each one. If it's one of the pulleys or tensioners, the noise should temporarily disappear after a light spray.

Other high pitch squeaks are usually caused by small leaks on the charge side of the intake, but usually aren't rpm related.

Have you had the EGR system worked on or previously altered?
The stainless steel laminated gaskets can shreik like a reed if the joint is loose.

Remove the serpentine belt and run the engine. No Squeal? then the problem is something the serp turns.

Most likely the one clutch inside the alternator pulley. To check, remove the belt and block the alternator's internal fan with a screwdriver. Try to turn the pulley in both directions and it should not turn in one direction and turn smoothly in the other direction.

Spraying lubricant on your belt will cause your belt to deteriorate (rot) over time.

Thanks for the great ideas. I will see if I can figure it out this weekend.

My money is on the alternator pulley. I already changed them for both my BEW and BRM

Shoot those are all great ideas but my go to squeal finder is a piece of garden hose. I can find the exact point of the squeal with it by listening through the hose while moving it around the engine bay. Gotta get the broom handle out for lifter, rod or other internal knocks. Old school farm boy tricks. Just my 2 cents

If it's not from the belt side, I'd put my money on either a small leak in the EGR piping like JETaah suggested or a worn VNT actuator arm bushing, had that happen on a car I used to have. It squealed when the boost peaked, as soon as the actuator started to open it would stop.