Hopefully, your grandfather also left information along with his paperwork to help you determine where the money is. If not, you will need to do some detective work, if you are going to find your account. It is also possible that the account may have been closed, which will make things just about impossible for you. You could check with the unclaimed property division of the state, if your grandparents are no longer living. This is one reason why it is important to communicate with your loved ones, when you set things up in this manner. Best of luck on your search!
*** LEGAL DISCLAIMER I am licensed to practice law in the State of Michigan and have offices in Wayne and Ingham Counties. My practice is focused in the areas of estate planning and probate administration. I am ethically required to state that the above answer does not create an attorney/client relationship. These responses should be considered general legal education and are intended to provide general information about the question asked. Frequently, the question does not include important facts that, if known, could significantly change the answer. Information provided on this site should not be used as a substitute for competent legal advice from a licensed attorney that practices in your state. The law changes frequently and varies from state to state. If I refer to your state's laws, you should not rely on what I say; I just did a quick Internet search and found something that looked relevant that I hoped you would find helpful. You should verify and confirm any information provided with an attorney licensed in your state.