It is not lawful to get a car financed by bank on instalments, as in this case one will have to pay interest on each instalment, which is haram. As it is haram to take interest, in the same way it is haram to give interest too. However, if you buy the car in a way that the bank declares the price of car and the total amount upto the last instalment including interest whatever it may be as the total price of car and you buy the car from the bank for the total price and then pay the price in instalments, then it shall be lawful. And thus you would be saved from the sin of paying interest.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband