Thats not what AZSonicSnake asked. He wanted to know why the blue stripe was on his driver side head. It was there to identify that the warranty/recall or TSB had been performed. Its Fords claim that the redesigned head cured the cooling issue which resulted in the ticking noise. The AFTERMARKET came out with the fitting to replace the freeze plug in the driver side head that lets coolant excape the rear of the head like the passenger side does from the factory. But again thats not the question AZSonicSnake asked.