Short answer. Yes. Article 1947 treats this arrangement as a precarium, since the use of your vehicle is merely tolerated by you as owner without any stipulated duration or purpose. As bailor in a precarium, you may demand the vehicle back at will, without needing to give a reason or wait for a fixed period.
What the law says
The bailor may demand the thing at will, and the contractual relation is called a precarium, in the following cases: (1) If neither the duration of the contract nor the use to which the thing loaned should be devoted, has been stipulated; or (2) If the use of the thing is merely tolerated by the owner.
Civil Code, Article 1947 — Precarium. Read the full provision →
Why letting your neighbor use the car out of goodwill fits this article
Article 1947 describes exactly the kind of loose, goodwill arrangement you have with your neighbor: the bailor may demand the thing at will, and the contractual relation is called a precarium, in the following cases: (1) If neither the duration of the contract nor the use to which the thing loaned should be devoted, has been stipulated; or (2) If the use of the thing is merely tolerated by the owner. You never set a fixed period for how long your neighbor could use the vehicle, never specified exactly what the vehicle was to be used for, and you are simply tolerating the use as the owner. Either condition alone is enough to make this a precarium.
Why a precarium gives the owner the strongest position
A precarium is treated differently from an ordinary loan of a thing where the parties agreed on a set duration or a specific purpose for the loan. In those ordinary cases, the borrower can generally expect to keep using the thing until the agreed period ends or the purpose is fulfilled. A precarium exists precisely because none of that structure is present, and the law responds by giving the owner the right to demand the thing back at will, meaning at any time the owner chooses, without needing to point to a breach or wait for a particular event.
What 'at will' means for you and your neighbor
Because the arrangement is a precarium, you are not bound to give your neighbor advance notice, a specific reason, or a grace period before asking for the vehicle back, since the very nature of a precarium is that its continuation depends entirely on the owner's ongoing tolerance. Your neighbor's use of the vehicle exists only for as long as you are willing to allow it, and your decision to end that use is sufficient by itself to bring the arrangement to a close under Article 1947.
What this means in practice
If you want your vehicle back, you can simply inform your neighbor that the arrangement is over and ask for its return, since no formal notice period or justification is legally required for a precarium. It remains good practice to communicate clearly and give your neighbor a reasonable opportunity to actually return the vehicle, since the legal right to demand it at will does not by itself resolve practical questions like where and when the handover will happen.