159 2.4 Whine / Disney Snore
So ever since I purchased my 159 2.4 (210) a couple of months back I've had this really annoying noise upon throttle lift off. At first I was convinced it was a slipping drive belt but I've now changed both the large serpentine belt and the smaller stretch belt, and also the alternator freewheel clutch pulley and the noise is no better. To be honest the stuff I've replaced didn't really seem worn or damaged anyway.
To describe the noise it's like a skittish whistle/screech that lasts 1-2 seconds. The best thing I can compare it to would be the noise a Disney character would make after snoring upon exhale whilst being violently shaken at the same time?????!!!! Yes, I probably do need to see someone about my mind!
The noise is most noticeable in first and second gear, occurs only on lifting off the throttle in preparation for changing gear but is not affected by clutching.
My next port of call was going to be the tensioner on the serpentine belt, or maybe the idler but again, the arm moves freely enough and it doesn't appear overly worn..
I've also checked for leaks in the turbo hoses etc but the noise doesn't appear to happen under boost and I can't seem to find any leaks..
Anyone ever come across this weird problem before?!