No worries, Kevin. For starters, the Honda plant is nowhere near the Fukushima Daiichi power station (in fact, your Civic will probably be built in Ohio). For another, even if the plant were in the same prefecture, in order to pick up any radioactivity, the plant would have to actually be located within the confines of the power station. The delays in Japan were due to power-supply issues and the general devastation resulting from the earthquake and tsunami, not anything to do with radiation release.
In short, feel free to purchase Hondas, or virtually any other make of car, to your heart's content; there will be no significant levels of radiation involved.
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Sodium is a metal that reacts explosively when exposed to water. Chlorine is a gas that'll kill you dead in moments. Together they make my fries taste good.