A thermostat that opens at a lower temperature will not make your engine run cooler. It will make it take longer to warm up. The same amount of coolant moves through a stock or lower temp thermostat. The engine generates the same amount of waste heat with either thermostat. The radiator can remove the same amount of heat from the coolant. The only difference is that the "cooler" thermostat lets coolant go to the radiator earlier during warmup which slows the warmup and can keep the engine in the warmup mode for a while longer. Engines are carefully designed to work in a temperature range. Oil is designed to have the right viscosity in the designed temperature range. The emissions are designed to work in the designed temperature range. It is best to get to that operating temperature quickly. If you want it to run best let the cooling system run the way it was designed to.
If you have heating issues or you have some extreme use case for your truck, then there are ways to increase cooling capacity, but a thermostat that opens at a cooler temperature is not one of them.
If you have heating issues or you have some extreme use case for your truck, then there are ways to increase cooling capacity, but a thermostat that opens at a cooler temperature is not one of them.
