I owe 16,000 in a car loan. If I pay 8,000 towards it will it lower the amount of months that I have to pay or will it lower the price of the payments?
I can't say for sure without knowing the specifics of your contract. But in most cases, the monthly payment is fixed, so paying extra will decrease the number of months you will need to make payments.
Also be sure to check if there is any early payment/prepayment penalty included in your contract.