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How to Replace Thermostat & Gasket 02-10 Mercury Mountaineer 4.6L V8

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  1. step : Removing the Engine Cover (0:37)
    • Disconnect the negative battery cable with an 8mm wrench
    • Remove the two 11mm nuts from the engine cover
    • Lift the engine cover up and off
    • Remove the hose from the clip on the back
  2. step : Removing the Thermostat (1:15)
    • Push the teeth together on the radiator hose clamp and slide it back
    • Twist the radiator hose off and set it aside
    • Remove the two 10mm bolts from the housing
    • Tap the housing while lifting it up
    • Pry out the O-ring around the thermostat with a flat blade screwdriver
    • Vacuum out the area and clean it with a wire brush while vacuuming
  3. step : Installing the New Thermostat (2:28)
    • Push the thermostat into place
    • Push the O-ring into place
    • Insert the thermostat housing into place
    • Tighten the two 10mm bolts to the thermostat housing
    • Tighten the 10mm bolts to 19 foot-pounds of torque
    • Push the radiator hose into the housing
    • Tighten the hose clamp with a pair of pliers
  4. step : Reinstalling the Engine Cover (3:48)
    • Insert the engine cover into place
    • Tighten the two 11mm bolts to the engine cover
    • Push the hose onto the clip in the back of the engine cover
    • Connect the negative battery cable
  5. step : Refilling the Coolant (4:16)
    • Twist off the coolant bottle cap
    • Start the engine
    • Add anti-freeze to the cold fill line

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Hi, I'm Mike from 1A Auto. I hope this how-to video helps you out, and next time you need parts for your vehicle, think of Thanks!

In this video, we're going to show you how to replace the thermostat on this 2003 Mercury Mountaineer. The items you'll need for this are a new thermostat from, a 10mm and 11mm socket and ratchet, a pair of pliers, flat blade screwdriver, vacuum, wire brush, and a torque wrench.

Start off by loosening up this 8mm bolt on your negative battery cable. Pull the negative battery cable free, and then remove these two 11mm nuts. Lift the engine cover up and off and then open up the clip on the back and pull the hose straight.

Using a pair of pliers, just push the teeth together on this hose clamp and slide it back. Then twist that hose free and just set that hose aside. Now remove these two 10mm bolts. To help you get the other bolt out, it's easier if you just remove this 10mm nut right here and then just pull that wire out of the way. Then that bolt pulls right up and out. Then just tap the housing while lifting up on it and it will pull free. Pry out this little O-ring with a flat blade screwdriver. Now, your thermostat will just lift up and out.

Then you want to just clean up the area where your thermostat goes, but you don't want any debris to fall down into the engine, so if you're using a wire brush, just have a vacuum on to suck up all the degree. When it's cleaned up, put your new thermostat down into place.

Take your new O-ring and push it into place. Take your housing, push it down into place, and then replace those two 10mm bolts and tighten them up. Now, torque those two 10mm bolts to 19 foot-pounds, and then replace that wire and to replace the 10mm nut just tighten that up. Take this hose and push it back into place. Then, using your pair of pliers, just slide that hose clamp back up in place. If it doesn't pop open on its own, use a flat blade screwdriver to just hit the tab separately. Take your cover, push it back down into place. Make sure its clips push back in, then replace those two 11mm nuts, tighten them up, and then push that hose back into the clip and close the clip. Reconnect your negative battery cable and tighten it back up and then you're all set.

Any time, you do any service to the cooling system, you want to make sure you add radiator fluid. This is for motor product. You need to use the gold style fluid or make sure it's compatible. This is a cold fill line. You want to be within this range. Make sure the engine is cool when you're filling it. If you've done extensive service or draining a lot out of it, you want to do this and start up your engine, run it, let it cool down and you'll probably do it a few times before you add back all the coolant in, but anytime you service your cooling system, refill it and recheck it a few times the first few times you drive it.

We hope this video helps you out. Brought to you by, your source for quality replacement parts and the best service on the Internet. Please feel free to call us toll-free, 888-844-3393. We're the company that's here for you on the Internet and in person.

Tools needed for replacement:

    General Tools

  • Wire Brush

  • Materials, Fluids, and Supplies

  • Anti-Freeze

  • Pliers, Cutters & misc Wrenches

  • Needle nose pliers

  • Ratchets & Related

  • Torque Wrench
  • Ratchet

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 10mm Socket
  • 11mm Socket

  • Specialty Tools

  • Vacuum

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96-12 Ford; 98-12 Lincoln; 02-11 Mercury Multifit (195 Degree) Thermostat & Gasket

Thermostat & Gasket 2 Piece Set DIY Solutions

This part replaces:

  • DIY Solutions HVA03408

Part Details

  • Quantity: 2 Piece Set
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