According to Bloomberg, Toyota has known about issues with valve springs in its V8 and V6 engines since 2007. The news confirms the information we received from an anonymous source within the company. Toyota says that the earliest complaints came from customers in Japan, but the company felt that the issue was fairly rare and didn't order a recall. Now that it has become clear that the issue isn't a fluke, the automaker has issued a recall in Japan and will notify the National Highway Transportation Safety Administration of the problem this week.
Toyota says that the defect is caused by the presence of contaminates within the spring material. The company has since addressed the problem by building the valve springs thicker than what was originally specified, and so far, the fix seems to be working.
Toyota says that around 270,000 vehicles are affected by the faulty springs, and of those, around 138,000 Lexus models are in the US.