So.. had 1.7 cdti astra h (06) for a few months now and has been a nightmare. ive had a squeel coming from the engine when under load and when it starts up, ive been to vauxhall and they diagnosed it as the tensioner, was replaced, noise went for a week and then came back with a vengeance. So they then told me to do water pump and idler (tensioner was again replaced under warranty). Same thing again, went away for a week and after a long motorway journey it returned. Anyone who knows what the problem is that would be grand.