Strange noise from '93 300E (2.8) engine

[dacia]

Hello everyone,

I hear some noise coming from the intake side of the engine (104.942). It seems to originate from that little black plastic box bolted on top of the intake manifold. It sounds like a wornout ball-bearing and the intensity changes when I rev. the engine. The noise was always there however it had a much healthier sound at the time I bought the car, about 50K miles ago. Anyone experienced this?
Thanks for your help,

Alex