🔧 Grand Cherokee - Thermostat Replacement

The thermostat controls coolant flow through your Grand Cherokee’s 5.7L HEMI cooling system. Replacing it involves draining some coolant, removing the thermostat housing, installing a new thermostat and seal, then bleeding air from the system.

Difficulty Level: Beginner-Intermediate | Estimated Time: 1.5-2.5 hours

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⚠️ Safety & Precautions

• ⚠️ Only work on the cooling system when the engine is completely cold. Hot coolant can cause severe burns.
• ⚠️ Do not open the radiator cap or coolant reservoir cap while the engine is hot.
• ⚠️ Coolant is toxic to people and pets. Catch all drained coolant and dispose of it safely.
• ⚠️ Keep coolant off belts, pulleys, and electrical connectors.
• ⚠️ Battery disconnect is not normally required for this repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• 13mm socket
• 3/8-inch ratchet
• 3/8-inch extension 6-inch
• Flat-blade screwdriver
• Hose clamp pliers
• Drain pan 2-gallon minimum
• Plastic trim tool
• Gasket scraper plastic
• Torque wrench 3/8-inch drive inch-pound
• Funnel spill-free coolant filling kit
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Engine coolant thermostat - Qty: 1
• Thermostat housing seal or O-ring - Qty: 1
• Mopar-compatible OAT coolant concentrate or premix - Qty: 1-2 gallons
• Distilled water - Qty: 1 gallon if using coolant concentrate

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📋 Before You Begin

• 🅿️ Park your Grand Cherokee on level ground and let the engine cool completely.
• 🧊 A cold engine means it has sat several hours and the upper radiator hose feels cool by hand.
• 🧤 Put on safety glasses and nitrile gloves before opening the cooling system.
• 🪣 Place a drain pan under the front of the engine area before loosening any hose or drain point.
• ✅ Use only Chrysler/Jeep-approved OAT coolant. Do not mix HOAT, universal green, or unknown coolant types.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use both hands to lift the plastic engine cover straight upward from the rubber mounting grommets.
• If it feels stuck, use a plastic trim tool gently near the mounting points.
• Pull evenly to avoid cracking it.

Step 2: Relieve Cooling System Pressure

• Make sure the engine is cold.
• Slowly loosen the coolant reservoir cap by hand to release any remaining pressure.
• Remove the cap fully once you are sure there is no hissing pressure.

Step 3: Drain Enough Coolant

• Place the drain pan 2-gallon minimum under the radiator drain area or lower radiator hose area.
• Use a flat-blade screwdriver if your radiator drain petcock has a slotted head.
• Open the drain slowly and drain about 1 gallon of coolant, or enough so coolant level is below the thermostat housing.
• If the drain petcock is hard to access, use hose clamp pliers to loosen the lower hose clamp and carefully drain from the hose instead.
• Close the drain petcock by hand snugly, then lightly seat it with the flat-blade screwdriver if needed. Do not overtighten plastic parts.

Step 4: Locate the Thermostat Housing

• The thermostat housing is at the front of the 5.7L HEMI engine where the large lower radiator hose connects to the engine.
• The thermostat housing is the metal or plastic neck that holds the thermostat in place.
• Use a shop towel to wipe the area clean so dirt does not fall into the cooling system.

Step 5: Remove the Radiator Hose from the Thermostat Housing

• Use hose clamp pliers to squeeze the spring clamp on the lower radiator hose.
• Slide the clamp back onto the hose.
• Twist the hose gently by hand to break it loose.
• If stuck, use a flat-blade screwdriver carefully between the hose and housing lip. Do not cut or gouge the hose.
• Pull the hose off the thermostat housing and aim it toward the drain pan 2-gallon minimum.
• A little extra coolant will spill.

Step 6: Remove the Thermostat Housing Bolts

• Use a 13mm socket, 3/8-inch ratchet, and 3/8-inch extension 6-inch to remove the thermostat housing bolts.
• Remove the bolts evenly, a little at a time, so the housing comes away straight.
• Pull the thermostat housing off the engine.
• Note the thermostat direction before removing it. The spring side faces into the engine.

Step 7: Remove the Old Thermostat and Seal

• Pull the old thermostat out by hand.
• Remove the old thermostat seal or O-ring by hand.
• Use a plastic gasket scraper to clean the sealing surface.
• Do not use a metal scraper. Scratches can cause leaks.
• Wipe the surface with shop towels until it is clean and dry.

Step 8: Install the New Thermostat

• Install the new engine coolant thermostat in the same direction as the old one.
• The spring side goes into the engine.
• Install the new thermostat housing seal or O-ring in its groove.
• If the thermostat has a small bleed valve or jiggle pin, position it at the top when possible.
• Correct direction is very important.

Step 9: Reinstall the Thermostat Housing

• Set the thermostat housing straight onto the engine by hand.
• Start the housing bolts by hand to prevent cross-threading.
• Use a 13mm socket, 3/8-inch ratchet, and 3/8-inch extension 6-inch to snug the bolts evenly.
• Use a torque wrench 3/8-inch drive inch-pound to tighten the thermostat housing bolts to Torque to 12 Nm (105 in-lbs).
• Do not overtighten. The housing or seal can be damaged.

Step 10: Reinstall the Radiator Hose

• Push the lower radiator hose fully onto the thermostat housing by hand.
• Use hose clamp pliers to move the spring clamp back to its original position.
• Make sure the clamp sits behind the raised bead on the housing neck.
• Wipe away spilled coolant with shop towels.

Step 11: Refill the Cooling System

• Install the funnel spill-free coolant filling kit on the coolant reservoir.
• Add the correct Mopar-compatible OAT coolant concentrate or premix.
• If using concentrate, mix it 50/50 with distilled water before filling.
• Fill slowly until the coolant reservoir reaches the proper level mark.

Step 12: Bleed Air from the Cooling System

• Leave the funnel spill-free coolant filling kit installed with coolant in the funnel.
• Start the engine and set the cabin heat to full hot with the blower on low.
• Let the engine idle while watching the coolant level in the funnel.
• As air bubbles come out, add coolant as needed.
• Watch the temperature gauge. Shut the engine off immediately if it begins to overheat.
• Once the upper radiator hose gets hot and bubbles slow down, the thermostat has opened.
• Let the engine idle a few more minutes, then shut it off.

Step 13: Final Coolant Level Check

• Let the engine cool completely.
• Remove the funnel spill-free coolant filling kit.
• Install the coolant reservoir cap by hand until fully seated.
• Top off the coolant reservoir to the cold fill mark if needed.
• Reinstall the engine cover by pressing it down onto its rubber grommets by hand.

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✅ After Repair

• ✅ Start the engine and inspect the thermostat housing and radiator hose for leaks.
• ✅ Take a short test drive while watching the temperature gauge.
• ✅ After the test drive, let the engine cool completely and recheck coolant level.
• ✅ Recheck for leaks the next day after the engine has fully heat-cycled.
• ✅ If a coolant temperature fault code was present, clear it with a scan tool after confirming the repair.
• ✅ Dispose of old coolant at a proper recycling or hazardous waste facility.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $45-$120 (parts only)

You Save: $175-$300 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

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🎯 Ready to get started?

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