Thanks Klaus and others for your encouragement and good advise as today i attacked my timing belt and associated bits and peices. There was no way i could have done it without taking the pulley off and it was so quick that i wondered why i bothered trying otherwise. The gap between the pulley and protruding lug was only half the thickness of the belt ( so it felt )and as i mentioned previously the tensioner had disintergrated. The belt (volvo) had barely a mark on it yet the tensioner was destroyed. You would have thought that the tensioner would have been replaced with the belt. As stated the car has done 150k and i would hate to think that the belt has never been changed. How long do these mechanical tensioners last and are they normally reliable ? I still cant beleive my good luck, i should have bought a mega millions! Thanks again David