This might be of intrest to someone. My 99 Taco has 90K miles on it and still being covered by the ext. warr. I decided to let the local Certified Toyota dealer do it so it would be documented for warr. purposes. I waited and after they had it torn down I went back to look things over. The belt was still like new, so you could probably go at least 200K before changing it. The camshaft seals were not weeping, but I told them to go ahead and change them as they were accessible. The water pump seal was leaking so it was replaced at no cost to me under the warr. They also replaced the CS seal under warr. as it was weeping. The only thing negative was as I was inspecting the belt I spied the Damper pulley lying on the workbench. It had about 5 pieces broken off the edge. They had pried it off. I almost shit myself, the mechanic said it happens and he would clean it up. I said no, what you will do is put a new one on and they did(at thier expense, not mine.) Later on at home I got so steamed about this I emailed Toyota about what thier CERTIFIED mechs. did. They emailed me back with apologies and assured me that they would make everything right, and they did. From this experience I found out a few valuble items.
- Your timing belt is probably good for at least 200K miles.
- You should check the condition of your water pump seal probably every 50K miles.
- Same for the CS seal.
- Most important is DON'T TRUST ANYBODY. Just because they are "Certified" does not mean they are rocket scientists.
I hope this is of value to someone.