🔧 1500 - Thermostat Replacement

This repair replaces the engine coolant thermostat on your 1500. The thermostat controls coolant flow through the engine; if it sticks open or closed, your truck may run too cool, overheat, or set temperature-related fault codes.

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

---

⚠️ Safety & Precautions

• ⚠️ Work only on a completely cold engine. Hot coolant can cause serious burns.
• ⚠️ The cooling system is pressurized when hot. Do not remove the coolant pressure cap until the engine is cold.
• ⚠️ Your 1500 uses an eTorque mild-hybrid system, but this thermostat repair does not require high-voltage service. Do not touch orange high-voltage cables or components.
• ⚠️ Disconnecting the 12V battery is recommended before working around engine wiring. Use a 10mm socket on the negative battery terminal.
• ⚠️ Coolant is toxic to people and pets. Catch all drained coolant and dispose of it properly.

---

🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 13mm socket
• 1/4-inch drive ratchet
• 3/8-inch drive ratchet
• 6-inch extension
• Hose clamp pliers
• Flat-blade screwdriver
• Plastic trim tool
• Drain pan 2-gallon minimum
• Funnel
• Torque wrench inch-pound range
• Cooling system spill-free funnel kit (specialty)
• Shop towels
• Nitrile gloves
• Safety glasses

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Engine coolant thermostat assembly - Qty: 1
• Thermostat housing seal - Qty: 1
• Mopar-compatible OAT coolant concentrate or premix - Qty: 1 gallon
• Distilled water - Qty: 1 gallon if using concentrate

---

📋 Before You Begin

• Park your 1500 on level ground and let the engine cool completely, ideally overnight.
• Set the parking brake and shift the transmission to Park.
• Open the hood and remove the coolant pressure cap only after the engine is cold.
• Disconnect the negative 12V battery cable with a 10mm socket. The negative cable is the black cable marked with a minus sign.
• Use only OAT coolant approved for Ram cooling systems. Do not mix coolant types.
• A spill-free funnel is a funnel that seals to the coolant tank and helps remove trapped air while refilling.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Put on safety glasses and nitrile gloves.
• Lift the plastic engine cover straight upward by hand to release its rubber mounting grommets.
• Set the cover aside where it will not get stepped on.
• Pull upward evenly.

Step 2: Disconnect the 12V Battery

• Use a 10mm socket and 1/4-inch drive ratchet to loosen the negative battery terminal nut.
• Remove the negative cable from the battery post and position it so it cannot spring back onto the post.
• This helps prevent accidental electrical shorts while your hands are near engine wiring.

Step 3: Drain Some Coolant

• Place a 2-gallon drain pan under the radiator drain area.
• Use a flat-blade screwdriver if needed to open the radiator drain cock slowly.
• Drain about 1 gallon of coolant, then close the drain cock by hand or with the flat-blade screwdriver.
• Do not overtighten the plastic drain cock.
• Drain only what you need.

Step 4: Locate the Thermostat Housing

• Find the upper radiator hose where it connects to the engine-side thermostat housing on the front/top area of the 3.6L engine.
• The thermostat housing is the small coolant outlet that the radiator hose attaches to.
• Use shop towels around the area to catch leftover coolant.

Step 5: Remove the Radiator Hose from the Thermostat Housing

• Use hose clamp pliers to squeeze the spring clamp tabs together.
• Slide the clamp back along the hose, away from the thermostat housing.
• Twist the hose gently by hand to break it loose.
• If stuck, use a plastic trim tool to carefully loosen the hose edge. Do not cut or pry hard against the plastic housing.
• Pull the hose off the thermostat housing and aim it upward to reduce coolant loss.
• Twist first, then pull.

Step 6: Remove the Thermostat Housing Bolts

• Use a 10mm socket, 6-inch extension, and ratchet to remove the thermostat housing bolts.
• Support the housing with your free hand as the last bolt comes out.
• Remove the thermostat housing and thermostat assembly from the engine.
• Some coolant may spill. Use shop towels and keep the drain pan underneath.

Step 7: Clean the Sealing Surface

• Use shop towels to wipe the engine sealing surface clean.
• Use a plastic trim tool only if old seal material is stuck.
• Do not gouge or scratch the aluminum surface.
• Make sure no debris falls into the coolant passage.
• Clean surface prevents leaks.

Step 8: Install the New Thermostat Assembly

• Install the new thermostat housing seal onto the new thermostat assembly if it is not already installed.
• Position the new thermostat assembly on the engine exactly like the old one.
• Start all bolts by hand first to avoid cross-threading. Cross-threading means the bolt starts crooked and damages the threads.
• Use a 10mm socket and ratchet to snug the bolts evenly.
• Use an inch-pound torque wrench and 10mm socket to tighten the thermostat housing bolts to 12 Nm (106 in-lbs).

Step 9: Reinstall the Radiator Hose

• Push the radiator hose fully onto the thermostat housing neck by hand.
• Use hose clamp pliers to move the spring clamp back to its original position.
• Make sure the clamp sits behind the raised bead on the housing neck.
• Wipe the area dry with shop towels so leaks are easier to spot later.

Step 10: Refill the Cooling System

• Install the cooling system spill-free funnel kit onto the coolant pressure bottle.
• Use a funnel to add the correct Mopar-compatible OAT coolant mixture.
• If using concentrate, mix coolant with distilled water at a 50/50 ratio before filling.
• Fill until the coolant level stays near the proper mark on the bottle.

Step 11: Bleed Air from the Cooling System

• Reconnect the negative battery cable and tighten the terminal with a 10mm socket. Do not overtighten.
• Leave the spill-free funnel installed.
• Start the engine and set the cabin heater to the hottest setting with the blower on low.
• Let the engine idle while watching the coolant level in the funnel.
• Add coolant as the level drops.
• Watch for air bubbles. When bubbles slow down and the upper radiator hose gets warm, the thermostat has opened.
• Shut the engine off before it gets too hot or if coolant begins to rise rapidly.
• Remove the spill-free funnel kit carefully and install the pressure cap.

Step 12: Reinstall the Engine Cover

• Align the engine cover with its mounting posts.
• Press down firmly by hand until the cover seats into the rubber grommets.
• Check that no tools or towels are left in the engine bay.

---

✅ After Repair

• Start your 1500 and let it idle until it reaches normal operating temperature.
• Look around the thermostat housing and radiator hose for leaks.
• Take a short test drive while watching the temperature gauge.
• After the engine cools completely, recheck the coolant level and top off if needed.
• If the temperature gauge rises above normal, stop driving and let the engine cool before checking coolant level.
• Dispose of old coolant at a recycling center or repair facility. Do not pour it on the ground or into a drain.

---

💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $55-$140 (parts only)

You Save: $195-$310 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

---

🎯 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.