Grandparents Have To Do All The Work
You haven't seen the grandchild in years and now that he or she is turning 18, you think that you'll pick up where you left off. Sadly, that's usually not the case. The grandchild won't come knocking at your door, or most likely won't go looking for you.
The responsibility of re-connecting falls solely upon the grandparents' shoulders.
It's the grandparent who must locate the the grandchild, and once they do, it's the grandparent who does the calling, texting and visiting, that is if the grandchild is willing to re-connect.
It takes work and can be exhausting and frustrating.
In the end it's best not to hold on to expectations, which is not to say give up. The new relationship may not look like the one you had before, but tell yourself that's ok and continue living your life.