Radiator drain plug 97 Buick Park Avenue
well they do sell them, check with any auto parts store.
I don't think you'll find it at the auto parts store, may have to go to a radiator shop, junkyard or dealer
Dorman makes several types of petcocks for radiators, http://www.autozone.com/cooling-heating-and-climate-control/radiator-drain-plug , I used autozone for the example, but all the auto parts stores should have the same.
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