The car will not be put in his name until he pays the last installment

Firstly: 

There is nothing wrong with
buying by installments, whether you make a down payment or not, subject to
the condition that the contract is free of any stipulation of penalties to
be paid in the event of delay in paying installments, because such
conditions come under the heading of riba which is haraam. 

Secondly: 

Once the contract is
completed, you become the owner of the car, even if you have not paid any
installments yet; the car comes into your possession and its price becomes a
debt that you owe. 

Thirdly: 

The purpose of registering
the car in the purchaser’s name is protecting one’s rights; it is not a
condition of the transaction being valid. Ownership of the item sold passes
to the purchaser by virtue of the contract, whether it is registered in his
name or remains in the name of the seller. 

Fourthly: 

It is permissible for the
seller to stipulate collateral in order to protect his rights. He can make
the car itself collateral, so that the buyer cannot dispose of it by selling
it until he has paid off all the installments. The fuqaha’ stated that this
is permissible.  It says in Kashshaaf al-Qinaa’ (3/189): It is valid
to stipulate collateral for the price of the item sold. If he says, “I will
sell you this on condition that you keep it as collateral for its price,”
and he says, “I will buy it and give you collateral,” the purchase and the
pledge are valid. End quote. 

Based on that, if the delay
in registering the car in your name is in order to protect the seller, lest
you sell it before paying off the installments, then this does not affect
the validity of the sale, because of what we have stated above about the
registration being only for the purpose of protecting rights. But you own
this car according to sharee’ah, by virtue of the transaction. If it is
collateral, then it is not permissible for you to sell it until you have
paid off the pledge or are given permission by the seller. 

The Council of Senior
Scholars stated that it is permissible for the seller to keep the car in his
name for the purpose of protecting his rights, and said: The Council thinks
that the two parties to the transaction should do it in the proper manner,
which is selling the item and naming it as collateral for its price, and
protecting oneself by keeping the contract and ownership papers, and so on.
End quote. 

It remains for us to point
out that there is a similar method to that which we have mentioned, which is
leasing or rent-to-own, in which the one who is renting it out retains
ownership of the car until the last installment or rental payment is made,
but this contract is haraam. The Islamic Fiqh Council and the Council of
Senior Scholars have issued statements concerning this. Please see question
no. 14304 

And Allaah knows best.