Hi, I just finished doing the timing belt on my girlfriends aveo. All went well. I started running the engine to circulate the coolant, and slowly a rubbing sound turned up. It increased until I turned the engine off. I checked under the belt cover, and the belt has worked its way off the centre of the pulleys, away from the outer cover. I put brand new tensioner and idler, and I was pretty happy with how they were sitting. Could it be the water pump? What do you suggest I do?

Thanks