Third UOA for the Navigator, my main objective is to monitor the engine after some major repairs. One cylinder head was replaced early in its life and all timing chain tensioners/guides were replaced at 42,700 miles. Motorcraft filters were used for all OCI's. From left to right the oil in use was Schaeffer's 5w20, AMSOIL 0w20, and Motorcraft 5w20 (dealer installed after engine work). Most trips with this vehicle are over 15 miles, it gets some decent highway trips throughout the year with some occasional towing. Fuel economy has been a solid 12.6 MPG annual average for each of the last three years.