my fan belt recently came off i dont know if it snapped or just popped off as it was dark and i wasnt hanging about, it was old and needing replacing so am guessing it snapped, luckily i had a spare to get me home. bought 2 new belts slightly shorter than the original, (1 as a spare) and it keeps throwing the belt off? at 1st i thought it was just stretching as its a new belt, but it only seems to do it on WOT, am starting to think somethings out of line? but its never done it before. ant suggestions guys?