2014 with 3.5 liter engine with 110k well cared for miles. The vehicle has an intermittent growl that seems to be originating from the top rear of the engine. The car is so quiet that you do not hear it inside while driving, but you can hear it when entering or exiting the vehicle as the engine is running. I’ve already disconnected the accessory drive belt and determined that the growl is not from the front of the engine area. I thought it could be a cam bearing, but I’ve maintained the car since new and the oil is always clean. This is my 6th Lexus and I’ve never had any trouble with any of their engines, even with well over 300k miles.