When you default on a car loan, the lender could repossess your vehicle and your credit score will be negatively affected. Fortunately, most lenders will work with you to figure out a solution rather than repossess the vehicle. That said, any late payments or delinquency will stay on your credit report for seven years.
If you’re struggling to make your monthly payments, contact your lender immediately and before you miss a payment if possible. Reaching out to find a solution before defaulting shows you’re working in good faith. The lender may be more understanding and willing to help.