Whistles 1Z + Automatic

Hello, and first of all, thank you very much to the forum. You've helped me out many times.

Suddenly, my Golf started making a whistling noise and a rattling sound. Because diesel engines can sound quite loud, I can't tell if the noise is also present during acceleration, but it's quite noticeable during deceleration. I was able to pinpoint the sound to the front left side of the car. It's always there, whether the engine is warm or cold, and it persists even when in neutral.

Ruckelcheck wegen radlager oder evtl schleifende Teile habe ich geprüft. Seems okay.

Honestly, I have no idea what it could be. It didn't make any noise, and at 50 km/h, I can't exactly stick my head in the wheel well to try and locate it. Maybe someone has an idea, before I end up being nicknamed 'Quitscheentchen' (a derogatory term) here.

Best regards, Christian.