Ok, let's see here. I am chalking up engine failures to synthetic switching, yes. Well, when you own a vehicle for x amount of months (or years), and it runs perfectly fine, doesn't burn, leak or consume a drop of oil, then you switch to synthetic and shortly after have a complete failure out of the blue, you begin to wonder. And when it happens more than once, even more than twice, then you wonder even more. And when the technicians at the Ford dealership recommend dino-oil because they've seen issues with people using synthetic, you'd wonder even more.