The thermostat block the coolant from flowing into the radiator as the engine is warming. A fault through the thermostat can reason reduced engine performance and overheating, typically seen top top the instrument gauge panel.

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This article applies to the evade Ram third Generation (2002-2008).

Thermostats control engine temperature through opening and closing the i to the radiator. When the engine is very first started, it requirements to warm as fast as possible. Keeping coolant from getting to the radiator increases this process, to reduce wear and also emissions. Thermostats use both seals and also springs to move and also block coolant flow. No electronics are provided to do the thermostat operate. Instead, a wax pellet that melts when the coolant get a specific temperature draws the thermostat closed.

Thermostats can come to be stuck open or closed. A grounding closed thermostat will cause the engine to run cooler 보다 normal, if a stuck open up thermostat can cause the engine come overheat really quickly.


Materials NeededSocket set (10mm-18mm)Ratchet (1/2" or 3/8")3" ratchet extensionFlat head screwdriverThermostat3-4 gallons the coolant (buy HOAT (Mopar) coolant for trucks v it currently installed)Drain pan3/4" wrench

The ar of the thermostat because that the 5.7 hem engine and also the 4.7/3.7 engines room different. On the Hemi, the thermostat is situated on the engine in ~ the top radiator hose below the A/C compressor. The 4/7 and also 3.7 engine"s thermostat is situated on the lower radiator hose near the harmonic balancer.

Step 1 – drain the coolant from the radiator

Remove the radiator lid by pushing it down, and also then twisting that counterclockwise.

At the driver"s next bottom edge of the radiator is a drainpipe blocked by a plug. Rotate this plug counterclockwise through a 3/4" wrench ~ you location a drain pan in ~ it.

Figure 1. The radiator drain plug.

Step 2 – remove the thermostat

To reach the thermostat, you should remove the water tap neck indigenous the engine. Two bolts hold it in place. Once it"s removed, the thermostat will certainly slide out.

Figure 2. The red circle indicates the position of the hose filler neck ~ above the 5.7 engine.
Figure 3. A chart of the 5.7 thermostat. Number 1 suggests the water tap filler neck bolts. Number 2 indicates the filler neck.
Figure 4. The thermostat location on the 4.7 and 3.7 engines. You have the right to see the harmonic balancer at the reduced right next of the image.
Figure 5. A diagram of the thermostat ~ above the 4.7 and also 3.7 engines.

Step 3 – download the new thermostat

Some thermostats come with an air bleed valve and notch in ~ the sheet of the diaphragm. The notch must be filed right into the brand-new thermostat to look like the factory thermostat for appropriate fitment v the O-ring. The bleed valve is not required; although, the does do bleeding the cooling mechanism of air easier. Transfer any gaskets native the original thermostat not discovered on the new thermostat if they space in great condition; otherwise, girlfriend will must buy brand-new ones. Make certain they are orientated properly for suitable fitment into the block and hose filler neck. The spring side of the thermostat will certainly be dealing with the engine.

Bolt the hose filler neck ago onto the engine with the thermostat correctly inserted inside.

Figure 6. You deserve to see the bleed valve on the face of the initial thermostat ~ above the left. Both thermostats have actually the notch on the edge.
Figure 7. The red arrow points come the slot in the hose filler neck the fits to the thermostat O-ring.

Step 4 – Fill and bleed the cooling system

You will need about three gallons of 50/50 combined coolant to fill the cooling system. For trucks making use of HOAT coolant, be sure to usage the very same type. Because that the 4.7 and also 3.7 engines, eliminate the top radiator hose and also fill the engine v as much coolant together possible.

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The rest of the instructions use to all engines. To fill the radiator, and then to fill the coolant recovery tank to the cold complete mark. Leave just the restore tank"s cap off. Currently start the engine and also turn the warm to the max setting. It will take numerous minutes for the cooling system to warm and move air through the system. Once the temperature gauge reaches about 1/4 that the means to the half mark, close up door the engine off. Optimal off the coolant in the restore tank as needed throughout this procedure. Placed the recovery tank cap ago on and start the engine again. If the temp gauge rises over halfway, you might still have actually air in the system and also will must repeat the bleeding procedure as soon as the engine is cool enough to carry out so.