if you have the PD engine it will be a garrett unit with variable vain. They are prone of breaking if not serviced correctly. If a new unit is fitted you will have to change the oil pipes as most suppliers will not supply the turbo unless you order the pipes. To be honest I have changeed loads of these when I worked at Seat in Darlo. I would try avoid 2nd hand ones. Hope this shed a bit of light on some thing.