🔧 Grand Cherokee - Thermostat Replacement

Your Grand Cherokee’s thermostat controls coolant flow to keep the engine at the correct temperature. Replacing it usually means replacing the thermostat housing assembly, then refilling and bleeding (removing air from) the cooling system.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully before opening the cooling system (hot coolant can cause severe burns).
• ⚠️ The electric cooling fan can turn on by itself; keep hands/tools clear of the fan area.
• ⚠️ Support the vehicle with jack stands if you raise it—never rely on a jack alone.
• ⚠️ Coolant is toxic; keep it away from kids/pets and dispose of it properly.
• Disconnecting the battery negative terminal is recommended for safety while working near the fan.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Drain pan (at least 3-gallon)
• Funnel
• Trim clip removal tool
• Flat-blade screwdriver
• 8mm socket
• 10mm socket
• 13mm socket
• 15mm socket
• 3/8" ratchet
• 3/8" extension set
• Torque wrench (inch-pound)
• Hose clamp pliers
• Pick tool
• Shop rags

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Thermostat housing assembly (thermostat included) - Qty: 1
• Engine coolant (OAT, 50/50 premix) - Qty: 2-3 gallons
• Upper radiator hose clamp (optional if original is weak) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Let the engine cool completely (best is overnight).
• Open the hood and remove the coolant reservoir cap only when fully cool.
• Use a 10mm socket to disconnect the battery negative terminal and position it so it can’t spring back.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise the front (if needed) and access the drain

• Use a floor jack (rated 3-ton minimum) to lift the front safely, then support with jack stands (rated 3-ton minimum).
• Place a drain pan (at least 3-gallon) under the radiator drain area.

Step 2: Drain the coolant

• Remove any lower splash shield fasteners as needed using a trim clip removal tool and 8mm socket.
• Open the radiator drain (petcock) carefully and drain into the drain pan. Use a flat-blade screwdriver only if your drain style requires it.
• Tip: Keep the drain pan centered; flow can change.

Step 3: Remove the air intake duct/air box as needed

• Loosen the intake clamps using an 8mm socket (or flat-blade screwdriver, depending on clamp style).
• Unclip/unbolt the air box using a 10mm socket, then lift it out to make room.

Step 4: Relieve belt tension (if it blocks access)

• Use a 15mm socket and 3/8" ratchet to rotate the belt tensioner and slip the belt off the front accessory pulley if needed for access.
• Tip: Take a photo of the belt routing.

Step 5: Disconnect hoses at the thermostat housing

• Use hose clamp pliers to compress the spring clamp(s), then slide the clamp back on the hose.
• Twist the hose gently to break it loose, then pull it off. Use a pick tool carefully if the hose is stuck (do not gouge the plastic housing).
• Catch remaining coolant with the drain pan and use shop rags to keep the area clean.

Step 6: Remove the thermostat housing assembly

• Remove the thermostat housing mounting bolts using a 10mm socket with a 3/8" extension set.
• Lift the housing out. Make sure the old seal/O-ring comes out with it (don’t leave pieces behind).

Step 7: Clean the sealing surface

• Wipe the engine mating surface with shop rags. Use a pick tool only to remove stuck gasket material gently.
• Do not scratch the aluminum sealing surface.

Step 8: Install the new thermostat housing

• Place the new thermostat housing assembly in position by hand.
• Start all bolts by hand to avoid cross-threading.
• Tighten the bolts evenly using a 10mm socket.
• Torque to 12 Nm (106 in-lbs) using a torque wrench (inch-pound).

Step 9: Reconnect hoses and clamps

• Push hoses fully onto their fittings.
• Use hose clamp pliers to reinstall clamps in their original positions.
• Double-check each clamp is centered over the bead/ridge on the fitting.

Step 10: Reinstall the belt and intake parts

• If removed, route the belt back and use a 15mm socket and 3/8" ratchet to rotate the tensioner and slip the belt into place.
• Reinstall the air box and ducting using a 10mm socket and tighten clamps with an 8mm socket.
• Reinstall any splash shields using a trim clip removal tool and 8mm socket.

Step 11: Refill and bleed the cooling system

• Lower the vehicle if it’s on stands (use the floor jack and remove jack stands safely).
• Fill the coolant reservoir slowly using a funnel with engine coolant (OAT, 50/50 premix).
• If your thermostat housing has a bleed screw, open it carefully with the correct tool for your bleeder (commonly a small hex). Add coolant until a steady stream (no bubbles) comes out, then close it.
• Reconnect the battery negative terminal using a 10mm socket.

Step 12: Warm-up and final top-off

• Start the engine and set the cabin heat to HOT (this helps circulate coolant through the heater core).
• Let it idle and watch the temperature gauge. Inspect the thermostat housing and hose joints for leaks using safety glasses.
• Shut the engine off, let it cool, then top off the reservoir to the proper level using a funnel.

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✅ After Repair

• Test drive 10–15 minutes and confirm the gauge stays normal and heat works.
• Recheck for coolant leaks around the thermostat housing and hoses after the drive.
• When fully cool again, recheck coolant level and top off if needed.
• If you get a check engine light (often for coolant temp), scan codes and verify connectors/clamps are secure.

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💰 DIY vs Shop Cost

Shop Cost: $450-$900 (parts + labor)

DIY Cost: $60-$180 (parts only)

You Save: $270-$840 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 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.