Many people create a new Facebook login so not to use their personal Facebook account on their work page. This is wrong, and Facebook is starting to remove accounts that use generic email addresses and names.
The best way is to login as yourself using your personal account, and create a business page. To learn how to do that, read this.
Once created, go to the page settings and select users. Here you can add other people to help manage the page, and even remove yourself.
When someone new starts at your dealership, you can add them as an admin, and they will be able to log in and access the business Facebook page using their login credentials. This also helps keep things secure as you will be able to see who posts and makes changes to your page, and if that person leaves your business, you can simply remove them from the user list, and even ban them from the page if need be.
Using a fake or generic account on Facebook will lead to issues including the same login being used in multiple places, as well as multiple people using the one login.
If you are using Facebook Business Manager, user management is very easy, and you can also assign partner roles simply which is great for new advertising campaigns where agencies need page access.