Engine/gear squeaks

Hello, just come from a ride of 120km, of which 90km highway. Now I’m driving to my parking lot, let the window down and hear this squeak. Sound first like the brakes, which can squeak a bit while grinding slightly, but the noise did not disappear in the stand either. bonnet on – the noise does not come from the passenger side of the engine, where the belt drives the aggregates and also the timing belt runs, but from the driver side, it can’t be located more precisely. On the engine it’s also quite loud, the running noise drowns clearly. If I give some gas, it disappears from about 1500 rpm. This has occurred once before after a long distance, but not every time. Does one of you have an idea? V40, Bj. 98, 1.8 85KW