How do I find an account my grandfather left me

There is no central database of bank accounts that you can search to see if there's an account in your name or your grandfather's name.  have you asked family members who might know the answer to this question?  have you checked the PA bureau of unclaimed property?  You might also send a request for information to the bank(s) where he typically held accounts to see if there's any account with your name.  If the account did not have your name on it at all, none of these suggestions will result in you getting the money though.  When he died, was an estate administration proceeding opened for him?  The personal representative of the estate could assist with this investigation or might know the answer already.