Various methods and systems are provided for a thermal management system of an engine. A method for an engine may comprise adjusting an engine speed during an engine start event that includes an engine cranking activity from a first engine speed to a second engine speed, where the adjusting is based on a sensed oil temperature; adjusting a first resistance of a radiator primary return line of a thermal management system to a first resistance level; and adjusting the engine speed a duration after a start of the engine cranking from the second engine speed to a third engine speed, the third engine speed based at least in part on an engine torque demand, and selectively adjusting the first resistance between each of the first resistance level and a second resistance level based on the third engine speed, the second resistance level being lower than the first resistance level.