RAM 1500 Truck 4WD V8-4.7L (2008)
Thermostat: Description and Operation
Description
GAS ENGINE
CAUTION: Do not operate the engine without a thermostat, except for servicing or testing.
The 3.7L/4.7L/5.7L engines use a pellet-type thermostat that controls the operating temperature of the engine by controlling the amount of coolant flow
to the radiator. The 8.3L engine uses a movable sleeve type thermostat. 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.
On the 3.7L/4.7L engine the thermostat is designed to block the flow of the coolant bypass journal by 50% instead of completely blocking the flow. This
design controls coolant temperature more accurately.
The same thermostat is used for winter and summer seasons. An engine should not be operated without a thermostat, except for servicing or testing.
