after some use timing belts are bound to stretch. tighten the tensioner n c if it loosens again. if it does then u have a tensioner problem. and if this is the case id say find a buddy with some air n use a 3/4 inch impact. the thing will come right off. then put it back on with a 1/2 inch impact so that u will b able to break it lose again MUCH easier.

if u cant find any air id recomend the tool thats already been posted. but like everyone said make sure ur tools arent cheap n flimsy bc then ull run into more problems with broken tools. the jack handle end is a GREAT idea. g/l with what ever happens. keep us posted!