No, the US government should not bail out automakers, even with a low-interest loan, because the US government is distorting the market. If the automakers were strong enough to stay in business, there would be a private bank that would be willing to give them a loan. A government does not have the same incentives to make good choices about what should happen to a business.
I believe that in the United States businesses should be responsible for their own finances. Each corporation should budget for downturns, and it is inevitable that some companies will go bankrupt. It is not good practice for the United States to begin bailing out businesses, including automakers, because then the companies do not have an incentive to make wise business decisions.