I have a 328xit with 30,000 miles and a 2008 528xi with 6,000 miles. When I took the 528 for service I mentioned an occasional tapping noise, No Big Deal. Two hours later I get a phone call that there is a design flaw and they are replacing the entire head. So I take the 328 to them, same thing. Two complete heads in one week, no questions asked. What is up with that? No recall?