🔧 Thermostat - Replacement

The thermostat on your Grand Cherokee controls coolant flow so the engine can warm up and stay at the right temperature. If it sticks open or closed, you can get poor heat, overheating, or a check engine light.

Difficulty Level: Intermediate | Estimated Time: 2-3 hours

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⚠️ Safety & Precautions

• Work only on a cold engine. Hot coolant can cause severe burns.
• Keep the coolant system pressure cap closed until the engine is cold.
• Dispose of used coolant properly; it is toxic to people and pets.
• Battery disconnect is not required for this repair.
• Use care around the serpentine belt and radiator fan area.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• Ratchet
• Short extension
• Torque wrench
• Flat-blade screwdriver
• Hose clamp pliers
• Drain pan
• Funnel
• Floor jack (rated 3-ton minimum)
• Jack stands
• Safety glasses
• Gloves
• Shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Thermostat assembly with housing and gasket - Qty: 1
• Engine coolant - Qty: 1-2 gallons
• New hose clamp(s) - Qty: 1-2 if needed

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool completely.
• Raise the front of the vehicle only if you need extra access, and support it with jack stands.
• Have a drain pan ready before opening the cooling system.
• Keep track of hose routing.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Drain the coolant

• Place a drain pan under the radiator drain area.
• Open the radiator drain or loosen the lower hose carefully to drain enough coolant to get below the thermostat housing.
• If using the lower hose, use hose clamp pliers or a flat-blade screwdriver to move the clamp.
• Close the drain when the coolant level is low enough.

Step 2: Remove intake ducting for access

• Use a flat-blade screwdriver or 10mm socket to remove the air inlet duct or snorkel that blocks access to the thermostat area.
• Set the ducting aside where it will not get dirty.

Step 3: Remove the thermostat hoses

• Use hose clamp pliers to move the hose clamps back.
• Twist the hoses gently to break them free, then pull them off the thermostat housing.
• Catch any coolant that spills with shop towels.
• Twist first, then pull.

Step 4: Remove the thermostat housing

• Use a 10mm socket, ratchet, and short extension to remove the thermostat housing bolts.
• Lift the housing away from the engine.
• Remove the thermostat and old gasket if they stay behind.
• Clean the mating surface carefully with a shop towel.

Step 5: Install the new thermostat

• Install the new thermostat assembly and gasket in the same position as the old one.
• Make sure the gasket is seated flat and not pinched.
• Install the housing bolts by hand first.
• Use a torque wrench to tighten the bolts to 12 Nm (106 in-lbs).

Step 6: Reconnect the hoses and intake parts

• Push the hoses fully onto the housing nipples.
• Move the hose clamps back into place using hose clamp pliers.
• Reinstall the intake ducting using a flat-blade screwdriver or 10mm socket.

Step 7: Refill and bleed the cooling system

• Fill the system with the correct coolant mixture through the degas bottle or radiator fill point, depending on your setup.
• Use a funnel to avoid spills.
• Start the engine and let it idle with the heat set to full hot.
• Add coolant as the level drops.
• Watch for steady heat from the vents and normal temperature gauge operation.

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✅ After Repair

• Check for coolant leaks at the housing, hoses, and drain point.
• Verify the engine reaches normal operating temperature.
• Confirm cabin heat works properly.
• After a full cool-down, recheck the coolant level and top off if needed.
• If a warning light was on before, clear codes and road test the vehicle.

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💰 DIY vs Shop Cost

Shop Cost: $350-$650 (parts + labor)

DIY Cost: $60-$140 (parts only)

You Save: $290-$510 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-3 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.