This procedure covers removal and replacement of the thermostat housing on the 3.6L V6 Pentastar engine, including coolant draining, housing removal, thermostat replacement, and system refill.

Warnings

Tools required

Parts

• Thermostat housing assembly × 1 — Mopar 68105583AF or equivalent
• Thermostat (180°F or 195°F as specified) × 1 — Typically included with housing
• Housing O-ring or gasket × 1 — Verify if included with housing
• Coolant hose clamps × 3 — Worm-gear style, assorted sizes

Fluids

• Mopar OAT Coolant (Purple) — 2 qt

Preparation

1. Ensure engine is completely cold to the touch before beginning work
2. Park vehicle on level ground and engage parking brake
3. Disconnect negative battery terminal to prevent cooling fan activation
4. Remove engine cover by pulling upward on four retention points
5. Place drain pan under radiator drain petcock on driver side of radiator
6. Have replacement parts, gaskets, and fresh coolant ready before draining system

Procedure

1. 1

   Drain cooling system
   Open the radiator drain petcock located at the bottom driver side of the radiator by turning counterclockwise. Allow coolant to drain into pan. Once draining slows, close petcock hand-tight to prevent further leakage during repair. You do not need to drain the entire system, just enough to drop the level below the thermostat housing.
   Torque spec

   Drain Petcock8 Nm (6 lb-ft)
2. 2

   Remove upper radiator hose connection
   Locate the upper radiator hose connection at the thermostat housing outlet. Using pliers, compress and slide the hose clamp back approximately 2 inches away from the housing. Twist the hose gently while pulling to break the seal, then disconnect the hose from the housing. Have a shop towel ready as residual coolant will drain out.
   ⚠If the hose is stuck, use a pick tool to carefully break the seal. Do not pry against the thermostat housing as it is made of plastic and can crack.
   Torque spec

   Coolant Hose Clamps5 Nm (3 lb-ft)
3. 3

   Disconnect lower coolant hoses
   The thermostat housing has one or two smaller coolant hoses connected to it depending on configuration. Identify all hose connections to the housing. Reposition the hose clamps using pliers and disconnect each hose, noting their positions for reassembly. Expect residual coolant drainage.
   Torque spec

   Coolant Hose Clamps5 Nm (3 lb-ft)
4. 4

   Disconnect electrical connector
   Locate the coolant temperature sensor on the thermostat housing. Press the red safety tab and disconnect the electrical connector from the sensor. Move the wiring harness aside to provide clearance for housing removal.
   ℹ️If replacing only the housing and not the sensor, you may be able to transfer the sensor to the new housing. Apply thread sealant if reusing the sensor.
5. 5

   Remove thermostat housing bolts
   Using a 10mm socket, remove the housing mounting bolts. There are typically three bolts securing the housing to the engine block. Keep bolts organized as they may be different lengths. Note the location of any ground wires or brackets attached to the bolts.
   Torque spec

   Housing Bolts16 Nm (12 lb-ft)
6. 6

   Remove thermostat housing
   Carefully pull the thermostat housing away from the engine block. You may need to wiggle it gently to break the seal. Once removed, tip the housing to drain any remaining coolant into your drain pan. Remove the thermostat from the housing or engine block recess, noting its orientation with the spring side facing toward the engine.
   ⚠Do not use excessive force or pry tools that could damage the mating surface on the aluminum engine block. A damaged mating surface will cause coolant leaks.
7. 7

   Clean mating surfaces
   Thoroughly clean both the engine block mating surface and the thermostat recess. Remove all old gasket material, corrosion, and debris using a plastic scraper. Do not use metal scrapers that could gouge the aluminum. Wipe surfaces clean with brake cleaner and lint-free shop towels. Inspect for cracks, warping, or damage.
   ℹ️Any scratches or imperfections in the sealing surface can cause coolant leaks. The surface must be completely clean and smooth.
8. 8

   Install new thermostat
   Install the new thermostat into the engine block recess with the spring side facing INTO the engine block. The thermostat should sit flush in its recess. If the thermostat has an air bleed valve (small pin or jiggle valve), position it at the 12 o'clock position to allow air purging during refill.
   ⚠Installing the thermostat backward will cause engine overheating. The spring always faces toward the engine, and the sensor/pellet side faces out toward the housing.
9. 9

   Install new housing with O-ring
   Install the new O-ring or gasket onto the thermostat housing (or into the engine block groove, depending on design). Lightly lubricate the O-ring with fresh coolant to ease installation. Carefully align the housing onto the engine block, ensuring the thermostat stays seated in its recess. Press the housing firmly into place.
   ℹ️Ensure any alignment pins or dowels engage properly. The housing should sit flush against the block without gaps.
10. 10

    Install and torque housing bolts
    Start all three housing bolts by hand, ensuring they thread smoothly without cross-threading. Reinstall any ground wires or brackets in their original positions. Tighten the bolts in a crisscross pattern to ensure even sealing pressure. Using a torque wrench, torque all bolts to 16 Nm (12 lb-ft) in sequence.
    ⚠Over-torquing the plastic housing can cause cracks and immediate or delayed coolant leaks. Under-torquing will cause seepage. Use a torque wrench for this critical specification.
    Torque spec

    Housing Bolts16 Nm (12 lb-ft)
11. 11

    Reconnect coolant hoses
    Reconnect all coolant hoses to the thermostat housing in their original positions. Ensure each hose is pushed fully onto its fitting until it seats against the bead. Slide the hose clamps into position approximately 1/4 inch from the end of each hose. Tighten clamps to specification using a torque screwdriver or carefully with a nut driver.
    ⚠Over-tightening worm-gear clamps can cut through hoses or crack plastic fittings. Tighten until snug, then add the final torque specification.
    Torque spec

    Coolant Hose Clamps5 Nm (3 lb-ft)
12. 12

    Reconnect electrical connector
    Reconnect the coolant temperature sensor electrical connector to the sensor on the thermostat housing. Press firmly until you hear or feel it click into place. Verify the red safety tab locks properly.
13. 13

    Refill cooling system
    Using a coolant funnel with radiator cap adapter, slowly refill the cooling system with 50/50 mix of Mopar Purple OAT coolant and distilled water, or use pre-mixed coolant. Fill until coolant is visible at the base of the filler neck. Squeeze the upper radiator hose several times to help burp air from the system. Continue adding coolant as the level drops. Once full, install the radiator cap.
    ℹ️The 3.6L V6 has a total capacity of 13 quarts, but you will only need to replace approximately 2 quarts lost during this procedure.
14. 14

    Bleed air from cooling system
    Reconnect the negative battery terminal and reinstall the engine cover. Start the engine and allow it to idle with the heater set to full hot and fan on low. Monitor the temperature gauge. As the engine warms, the thermostat will open and coolant will circulate. Watch for the cooling fans to cycle on around 226°F. Run until the engine reaches full operating temperature and fans cycle at least once. Shut off engine and allow to cool for 15 minutes.
    ⚠️Stay clear of the cooling fan which can activate at any time. Do not open the radiator cap while the engine is running or hot.
15. 15

    Check coolant level and inspect for leaks
    Once engine has cooled, carefully open the radiator cap and check coolant level. Top off as necessary to the base of the filler neck. Check the coolant reservoir level and adjust to the COLD MAX line. Thoroughly inspect the thermostat housing, all hose connections, and radiator petcock for any signs of leakage. Wipe all surfaces dry and start the engine again briefly to verify no leaks under pressure.
    ℹ️Small seepage may occur initially as the O-ring seats. If leakage persists after a second heat cycle, re-torque housing bolts and verify hose clamp tightness.

Reassembly

1. Ensure all hose clamps are positioned correctly and tightened to specification
2. Verify coolant level is at proper level in both radiator and overflow reservoir
3. Double-check that all electrical connectors are fully seated and locked
4. Clean any coolant spills from engine bay to prevent corrosion and odors
5. Properly dispose of old coolant according to local environmental regulations

Verification

• Start engine and verify it reaches normal operating temperature (195-226°F) without overheating
• Confirm cooling fans cycle on and off automatically as designed
• Check that heater produces hot air when set to maximum temperature
• Inspect thermostat housing and all hose connections for leaks after full heat cycle
• Monitor coolant level over the next few days and top off if necessary as air pockets purge
• Verify no check engine light or temperature warning lights are illuminated

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