Loud Sreeching Noise in Engine compartment
 

I was cruising along today and started hearing a loud screeching noise from my engine. It is worse at idle .Doesn't matter if it is stopped or moving. With engine access off it almost sound like it is coming from the transmission instead of belts. No loss of power, coolant temp is fine. Please help!

remove the serpentine belt and see if it stops.

AOS maybe?

Thanks! Ill give it a shot!

What do I check next if it still is screeching? (2001) Boxter 5 speed Tiptronic)

Only a small puff at start up, goes away instantly. No leaking oil or consumption.

Have you confirmed it's not the ancillary belt?

Can you make & upload a video?

If it's gearbox or FW/clutch then it would be a bearing failed, with catastrophic failure imminent, though I'd expect you would experience loss of drive, and the noise would not be present at idle while stationary.