I hate described noises on here, but here goes.
It's coming from behind the glove box so could be anything forward of there. Definitely left side of car. Sounds like a whistle/gargle/burble. Like spinning a match box car wheel that part spins freely and smooth with intermitant buzz if it oscillates. I can't decide if it's air or a baring noise.
Car runs fine, no multi ram problems. Theres no air leaks from the vac pipes ESP by ac pipe. Pipes to vac tank by scuttle are fine. Cam belt has 20k left on it although I'm not sure on time, think end of year iirc according history. I suppose the cam belt cover could be rubbing.
Although having said all that a member here says his does the same. It's just the buzz from the cam wheels. Thing is I've never heard it before on another omega, only this one.
Thoughts please.
Check the cam belt is one, but I'm happy to let it run it's life as it's well documented in the history.