🔧 Thermostat - Replacement

The thermostat on your Ram sits in the coolant outlet housing and controls engine temperature. Replacing it usually means draining some coolant, removing the housing, and installing a new thermostat and seal so the engine can warm up and regulate correctly.

Difficulty Level: Intermediate | Estimated Time: 1.5-3 hours

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⚠️ Safety & Precautions

• Work only on a cold engine. Hot coolant can cause serious burns.
• Use jack stands if you raise the truck. Never rely on a floor jack alone.
• Keep hands and tools clear of the fan and belts if the battery is connected.
• Battery disconnect is not required for this repair, but it is okay to disconnect the negative cable if you want extra safety.
• Catch and dispose of coolant properly. It is toxic to people and pets.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• Ratchet
• Short extension
• Torque wrench
• Pliers
• Hose clamp pliers
• Drain pan
• Funnel
• Shop towels
• Safety glasses
• Nitrile gloves
• Jack and jack stands

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Thermostat - Qty: 1
• Thermostat housing seal - Qty: 1
• Engine coolant (Mopar 10 Year/150,000 Mile OAT, purple) - Qty: 1-2 gallons

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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.
• Open the hood and remove the engine cover if equipped.
• Place a drain pan under the radiator area before opening any hose connection.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Drain enough coolant

• Use a drain pan under the radiator drain or lower hose area.
• Drain the coolant level down below the thermostat housing.
• Drain only what you need.

Step 2: Remove intake ducting if needed

• Use a 10mm socket and ratchet to remove any air intake pieces that block access to the thermostat housing.
• Set the parts aside in order so they go back the same way.

Step 3: Remove the coolant hose

• Use hose clamp pliers or pliers to release the hose clamp at the thermostat housing.
• Twist the hose gently, then pull it off the housing.
• Expect some leftover coolant to spill.

Step 4: Remove the thermostat housing

• Use an 8mm socket, short extension, and ratchet to remove the housing bolts.
• Lift the housing straight off.
• Remove the old thermostat and old seal.

Step 5: Clean the sealing surface

• Use shop towels to clean the mating surface on the engine.
• Make sure no old gasket material or dirt is left behind.
• Do not scratch the aluminum surface.

Step 6: Install the new thermostat

• Install the new thermostat in the correct direction.
• Install the new thermostat housing seal.
• Set the housing in place by hand first so the seal stays aligned.

Step 7: Tighten the housing

• Use an 8mm socket and torque wrench to tighten the housing bolts evenly.
• Torque to 12 N·m (105 in-lbs).
• Do not overtighten. The housing can crack.

Step 8: Reconnect the hose and intake parts

• Push the coolant hose fully onto the housing.
• Use hose clamp pliers to reposition the clamp.
• Reinstall any intake ducts or covers with the 10mm socket.

Step 9: Refill the cooling system

• Use a funnel to refill with the correct coolant mix.
• Fill slowly to reduce trapped air.
• Install the cap securely once full.

Step 10: Bleed air and check for leaks

• Start the engine and let it idle with the heater set to hot.
• Watch the coolant level and add as needed.
• Check around the housing and hose for leaks.
• Torque recheck: Do not retorque unless a leak is present after cool-down.

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✅ After Repair

• Confirm the temperature gauge reaches normal and stays steady.
• Make sure the heater blows warm air.
• Check the coolant level again after the truck cools completely.
• Recheck for leaks the next day.

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💰 DIY vs Shop Cost

Shop Cost: $350-$700 (parts + labor)

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

You Save: $290-$560 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3 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.