Unless you are buying a new car, or refinancing a car, that loan will be a signature loan and you will get raped on the intrest. If you know you can pay this off in a year, I would look at summit, they have 1 year no interest on $500+ purchases with their new credit card.
Otherwise, just save up because it isn't a good idea to get so leveraged that you can't fix your car if it breaks.
I got a signature loan of $2500 - intrest was only 8% - by far worth the money to up the credit rating. I have a higher credit rating than 90% of the people living in my TownHouse subdivision - this according to the landlord. I replied, "REALLY??? That's funny, I even forclosed on a house 3 years ago when I get divorced." She did a quick check thinking there had been a mistake in my rating... but sure enough, it was on there.
Sometimes it's a good investment to pay a little interest.