Not a bit
The only thing that builds credit is a stream of on-time payments. It takes at least 24 months of timely payment to build a reasonable credit score, and years to build excellent score.
When you prepay student loan (or any other installment loan) you stop making timely payment. While this doesn’t hurt your credit, it doesn’t help it either because it stops building it.
However, keep in mind that credit scores are just a small part of any lending decision. For example, your debt-to-income ratio may have a bigger impact on the potential creditor’s decision. So are your employment stability and many other factors.
If you’re looking for a technique to raise your credit score prior to applying for a car loan (or any other loan for that matter) than read this. The described technique will raise your score immediately while lowering your debt-to-income ratio. This will get you better terms at any lender.
Good luck.