Section 1569 (Engine Cooling System - 2500 Hd): Engine: Thermostat: Description: 5.7L
WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Do not operate the engine without a thermostat, except for servicing or testing.
A pellet-type thermostat is used to control the operating temperature of the engine by controlling the amount of coolant flow to the radiator. On all engines the thermostat is closed below 195°F (90°C). Above this temperature, coolant is allowed to flow to the radiator. This provides quick engine warm up and overall temperature control.
Coolant leakage into the pellet container will cause the thermostat to fail in the open position. Thermostats very rarely stick. Do not attempt to free a thermostat with a prying device.