Using a car for collateral for a personal loan = a car loan.
Assigning a loan is just as much word as getting a new loan, except you arent bound by the terms that the last guy signed for. You also can get a car loan (secured) with lower interest. Most institutions finance any car regardless of age. All the care about is the loan-to-value. I dont see the point in dealing with this guy’s loan or bank, there’s no advantage.