Some 2018-2019 F-150 and Mustang vehicles equipped with a 5.0L engine may exhibit a light to moderate knocking type noise at idle (600-700 RPM) that is sometimes described as a quiet diesel type sound. The noise is usually more prominent on the passenger side of the vehicle toward the rear of the engine. As the engine comes up to operating temperature, the noise level increases slightly. This noise is not detrimental to engine function and has no short or long term effects on engine durability. This an operating characteristic of the 5.0L engine and no repairs should be attempted. Refer to the Service Procedure
