Owners of part of a business who guarantee auto or other asset loans for the company do not get title to the asset for which the loan is made. They may or may not even get credit for a capital contribution to the company, depending on the internal organizational agreements (partnership agreement for a partnership, organizational agreement for an LLC, bylaws or shareholders management agreements or other agreements among owners for a corporation) the owners have made with each other. If you want to get personal title to an entity asset, then get the agreement of other owners.
You should also be aware of the tax that may be owed for distributions from a partnership or from the business entity — the fair market or other agreed value of that asset, less (for entities taxed as partnerships) the partner (or LLC member) basis in the entity, which can include debt assumed. For corporations, the basis is just the cost of the owner’s stock, not that plus debts taken on for the entity.
These questions come up in small entity M&A frequently, since owners usually title and guarantee cars and car loans and many other assets as a part of entity property. They usually want to keep their personal cars, and those their families use, so untangling these things from company ownership and financial accounting is a useful part of either “clearing the underbrush” before a deal or resolving asset allocations in purchase agreements and at final closing.