You purchased the vehicle in good faith and the dealership is doing the same, repairing it to show good faith. If they had given you a problem in fixing the vehicle, then you might be justified in your concerns. They have a reputation to uphold and the replacement of a gasket is a small price to pay to maintain that reputation. If you were to walk away bad mouthing them for poor business practices, how long do you think they would stay in business, especially in today's times? My business thrives from word of mouth advertising, I must be doing something right because I am always busy