cuzman - I thought Australia spoke English?
caddymac - The 1st time my Corolla had this problem, it was covered under warranty. I looked on the forum then, and saw a few instances of this problem. The dealer also informed me that this problem was common (at that time).
When I was asking the part department about buying the part, I also asked them which part had been on replaced on my car before. As I understand it, the 2nd part was a 16620-22011. The latest part, which is the part I just put on the car is a 16620-22012.
I happen to know the way Toyota part numbers work. 22011 - A --> B (for example) is a minor change. It is normally invisible to the customer. 22011 - (whatever) --> 22012 - (nothing) is a major change to the part. I'm hoping the part was changed to improve its performance. I'm hoping I never have to replace it again. The only reason to major change a part is if there is something wrong with it. That should answer your question.
cuzman - On my engine (1.8L), you can't over tighten the belt ... the tensioner is designed to provide just the right amount of tension ... unless it screws up. Even if you change the position of say the alternator (I haven't checked, they might not have designed the position of the alternator to be adjustable because of the tensioner), the tensioner will create slack to keep the same tension on the belt.
- Amber