🔧 Thermostat - Replacement

Your Accord uses the thermostat inside the engine coolant outlet housing. Replacing it means draining some coolant, removing the housing, swapping the thermostat and seal, then refilling and bleeding the cooling system so the engine doesn’t overheat.

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

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⚠️ Safety & Precautions

• Work only on a completely cool engine. Hot coolant can cause serious burns.
• Dispose of used coolant properly. Pets are attracted to coolant and it is toxic.
• Keep the ignition off while working near the cooling fans. They can start unexpectedly.
• Battery disconnect is not required, but remove the negative cable if you want extra safety around the fan area.
• Use caution when opening the radiator cap. Only remove it when the engine is cool.

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🔧 Required Tools

You'll need the following tools for this repair:

• Metric socket set
• 10mm socket
• 12mm socket
• Ratchet
• Short extension
• Torque wrench
• Flat blade screwdriver
• Pliers
• Drain pan
• Funnel
• Shop towels
• Safety glasses
• Nitrile gloves
• Jack stands
• Floor jack (rated 3-ton minimum)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Thermostat - Qty: 1
• Thermostat seal / O-ring - Qty: 1
• Honda Type 2 coolant - Qty: 1-2 gallons
• Throttle body gasket - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool fully before opening the cooling system.
• Raise the front of the car only if you need more access to the drain area. Support it with jack stands.
• Have the new coolant ready before draining the old coolant.

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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.
• Use a flat blade screwdriver or pliers, depending on the clamp style, to move the lower hose only if needed for access.
• Open the radiator cap slowly when the engine is cold.
• Open the drain and let coolant flow into the pan.
• Keep the drain pan centered under the stream.

Step 2: Remove intake ducting for access

• Use a 10mm socket and ratchet to remove the air intake duct or air box pieces blocking access to the thermostat housing.
• Loosen any hose clamps with a flat blade screwdriver.
• Set the parts aside in order so reassembly is easier.

Step 3: Remove the thermostat housing

• Locate the coolant outlet housing on the engine.
• Use a 10mm socket with a short extension to remove the housing bolts.
• Pull the housing away carefully and catch any remaining coolant with shop towels.
• Remove the old thermostat and old seal/O-ring.

Step 4: Install the new thermostat

• Clean the housing and mating surface with a clean shop towel.
• Install the new thermostat in the same orientation as the old one.
• Install the new seal/O-ring.
• Reinstall the housing by hand first so the bolts do not cross-thread.
• Use a torque wrench and 10mm socket to tighten the housing bolts to 12 N·m (9 lb-ft).
• Snug evenly, then final-torque.

Step 5: Reinstall intake parts

• Reinstall the intake ducting and any removed covers.
• Use the 10mm socket and screwdriver to tighten all clamps and fasteners.
• Make sure nothing is left loose around the engine bay.

Step 6: Refill the cooling system

• Close the drain fully.
• Use a funnel to fill the radiator with Honda Type 2 coolant.
• Fill the reservoir to the MAX line.
• Leave the radiator cap off for the initial warm-up bleed.

Step 7: Bleed air from the system

• Start the engine and let it idle with the heater set to HOT.
• Watch the coolant level and add more as air escapes.
• When the upper hose gets hot, the thermostat has opened and the level may drop again.
• Keep topping off until the level stabilizes and no more bubbles appear.
• Install the radiator cap once the level stays steady.

Step 8: Check for leaks and verify operation

• Inspect the thermostat housing, hose connections, and drain area for leaks.
• Let the engine reach full operating temperature.
• Confirm the cabin heat works and the temperature gauge stays normal.
• If coolant level drops after a road test, top off the reservoir.

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✅ After Repair

• Recheck coolant level after the first drive and again after the next full heat cycle.
• Watch for warning lights, overheating, or coolant smell.
• Inspect under the car after parking for any drips.
• If the gauge climbs above normal, stop driving and recheck for trapped air.

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💰 DIY vs Shop Cost

Shop Cost: $320-$650 (parts + labor)

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

You Save: $275-$530 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?

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