There's the concept of an implied warrant of merchantability. If a thing has an ordinary purpose, and the thing sold fails in that ordinary purpose, the buyer has recourse.
Since a reasonable person buys a car as a long-lasting mode of transport, the sealed fuel tank would probably not meet expectations.
However, if the propulsion system were, say, nuclear fission, and the system lasted 5-10 years and then needed to be replaced, that might be a satisfactory product from this legal viewpoint. The NTSB and Department of Energy would have some things to say about it, though.
