Auctions typically sell the car “as is.” All buyers are “paying their money, and taking their chances” that a car that “seems” in good shape is. I saw one car flipping show called Texas Car Wars where one of the featured shops bought an older first gen Mustang at auction. They started working on it when one of the bodymen found a suspicious VIN tag. The car was indeed stolen. The car was confiscated, and the shop lost their money.
If the dealer actually did try to hide previous issues from you, you need to turn it in to your state’s attorney general, and find a another dealer you can trust.
And I don’t care HOW good a deal this may seem to be.
Walk away, and don’t look back.