1980's movie about a girl finding fountain of youth she and her turtle drinks from it. I remember a music boxes and the ending of the movie the turtle is near the side of the road an is still alive after decades of drinking from the spring.

That sounds like Tuck Everlasting: Tuck Everlasting (1981) - IMDb (http://www.imdb.com/title/tt0081664/)

It is based on a book (same title) by Natalie Babbitt and there is also a 2002 version of the movie.

No that is not it