The tension may change slightly but it's a cogged belt so the timing doesn't change unless it actually jumps a tooth which usually requires a pulley failure for that and when it does, the car no longer runs and all the valves are bent.
December, 3, 2012 AT 9:55 PM
Well I checked and it didnt jump teeth, pulleys were in good normal condition and I measured both old and new belts and the old on was longer, it was cracked and visibly worn to death. Looked ready to snap. Now that the new belt, waterpump, and tensioner are on it runs perfect.