when should the timing belt be replaced on a 99 2.5?

thanks in advance.

unfortunetly, I can't tell you a milege. If you look in a Haynes manual, they may give you an estimate. The best way to tell is to look at how it is physically. (If you want something to compare it to, go take a look at a new one in the store.) If it has missing chunks, it should be changed. If you can see any of the belts coming through the rubber, it should be changed. The most common sign is that the rubber will start to crack, mostly on the grooved side... a little is ok, but deep cracks and cracks in a row on consecutive peeks can lead to a snap. Depending on where you live, ie temp, salt exposure, etc It should last you anywhere from 4-6 years.