Car loan interest is flat rate, where as FD is compound interest. FD Wins.

I would choose put in FD not only for interest but also it's liquidity, I can use it in case emergency or invest into better return tools like stocks or businesses when the time is right.

Bank not only has few customers what

Sure there're many people can afford to loan a car, but inside their bank account / FD don't even have 20k savings.