Sorry for the late reply. The issue with the mkv gti is due to the timing belt tensioner. The timing belt itself was fine. In any case, the fix was temporary (for me) unfortunately. The tensioner is squeaking again and i'm out of warranty.
As far as your mkiv gti, i'm not all too familiar with mkivs but see if you can take your serpentine belt out all together. If the squeaks are gone, then it was your serpentine belt but if it isn't then it may be related to your timing belt and or components (rollers, tensioner, etc).
As far as your mkiv gti, i'm not all too familiar with mkivs but see if you can take your serpentine belt out all together. If the squeaks are gone, then it was your serpentine belt but if it isn't then it may be related to your timing belt and or components (rollers, tensioner, etc).