Can not help to point misconceptions here

Euro is Euro currency issued by ECB.

Euro dollar is US dollar deposited in oversea banks.

Third is your question: What happens if Greek default?

Theoretically, there is a EU directive that ECB guarantees $100k saving account deposit in their member banks if the bank fails.

But if Greek as a whole country defaults, the genes comes out the bottle. Not only other euro banks, but also major US banks, will incurr big loss. No one can predict savers will be able to recoup their savings and no one can predit ECB will fulfill their guarantee.

And if Greek defaults, the intention is to print their own money and their own money will devalue. Look out bank run as well.

I suspect all smart money are already exited Greek banks.