🔧 Thermostat - Replacement

The thermostat controls when coolant starts flowing through the radiator. If it sticks open or closed, your Accord can run too cold, overheat, or take too long to warm up. This repair involves draining coolant, removing the thermostat housing, and replacing the thermostat and seal.

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

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⚠️ Safety & Precautions

• Let the engine cool fully before opening the cooling system. Hot coolant can cause serious burns.
• Use jack stands if you raise the front of the vehicle. Never rely on a jack alone.
• Keep coolant off belts, rubber hoses, and painted surfaces.
• Dispose of old coolant properly. Do not pour it on the ground.
• No battery disconnect is required for this repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• 3/8-inch ratchet
• 10mm socket
• 12mm socket
• Extension bar
• Torque wrench
• Flat blade screwdriver
• Pliers
• Drain pan
• Funnel
• Safety glasses
• Nitrile gloves
• Jack stands
• Floor jack (rated 3-ton minimum)
• Shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Thermostat - Qty: 1
• Thermostat housing gasket or seal - Qty: 1
• Honda Type 2 coolant - Qty: 1-2 gallons
• Replacement hose clamps - Qty: 2

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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 needed for access.
• Have a clean drain pan ready before opening the cooling system.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Drain the coolant

• Place the drain pan under the radiator drain area.
• Open the radiator cap only when the engine is cold.
• Use a flat blade screwdriver or pliers to open the drain if equipped with a drain plug.
• Drain enough coolant so the thermostat housing can be removed without spilling.

Step 2: Remove intake ducting or covers for access

• Use the 10mm socket and 3/8-inch ratchet to remove any upper engine cover or air duct parts blocking access.
• Set all fasteners aside in order.

Step 3: Remove the thermostat housing connections

• Use pliers to release the hose clamp(s) on the thermostat housing.
• Twist the hose gently to break it free, then pull it off the housing.
• Twist first, then pull.

Step 4: Remove the thermostat housing

• Use the 10mm socket, 12mm socket, and extension bar to remove the housing bolts.
• Lift the housing straight off carefully.
• Remove the old thermostat and seal.

Step 5: Install the new thermostat

• Install the new thermostat in the same orientation as the old one.
• Install the new thermostat housing gasket or seal.
• Make sure the sealing surfaces are clean and dry.
• Reinstall the housing and hand-start the bolts.
• Torque to Honda service specification.

Step 6: Reconnect the hose and clamps

• Push the hose fully onto the housing neck.
• Reposition the clamp with pliers and make sure it sits behind the bead on the fitting.
• Replace any weak or rusty clamp with a new one.

Step 7: Reinstall covers and refill coolant

• Reinstall any removed ducting or engine covers using the 10mm socket.
• Use a funnel to refill with the correct coolant.
• Fill to the proper level in the radiator and reservoir.

Step 8: Bleed air from the cooling system

• Start the engine and let it idle.
• Turn the heater to hot with the blower on low.
• Watch the coolant level and top off as air escapes.
• When the radiator fan cycles and the upper hose gets hot, the thermostat has likely opened.
• Check for leaks around the housing and hose connections.

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✅ After Repair

• Let the engine reach full operating temperature and confirm stable gauge readings.
• Check the coolant level again after the engine cools.
• Inspect for leaks over the next 1-2 drive cycles.
• Watch for overheating, low heat output, or warning lights.

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💰 DIY vs Shop Cost

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

DIY Cost: $60-$160 (parts only)

You Save: $290-$490 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 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.