in my opinion it's up to you, but before you do it it's better to think about it again because you have to know that bitcoin has a high risk and it could be that what you predict is wrong so it will make you lose everything
I think your car is old and you want to change it otherwise I dont think it is better idea. In my opinion people should invest only extra money in bitcoin because it is very risky and there is no guarantee that you will win money after some time. you may lose your investment because it is not like regular business. Anyway good luck for you and hope that you will be happy.
Selling car for the crypto investment is irrelevant and investors do not think about it and do not consider it to sell something and start investment. This can be okay if you sell out your useless car that is not in need right now, now you have a new car and can sell out your precious one.
This will enable you to invest in Bitcoin or any coin that you see best for investment. Right now you will not find any other best choice other than Bitcoin as it show low price market availability.