Replace thermostat housing - 2003 Ford Explorer

Not from what I am reading. Here is the procedure from the AutoZone repair guide.....

2.8L & 3.6L Engines

1. Before servicing the vehicle, refer to the Precautions Section.
2. Drain the cooling system.
3. Disconnect the heater hoses from the heater core.
4. Remove the thermostat housing bolts.
5. Remove the thermostat housing with the heater pipes, hoses and bolts.
6. Carefully clean the sealing surfaces with a plastic gasket scraper.
7. Remove the thermostat.

To install:

1. Assemble the heater pipes and hoses to the thermostat housing.
2. Install a new gasket to the thermostat housing.
3. Install the thermostat.
4. Install the thermostat housing bolts to the thermostat housing. Partially install the thermostat housing bolts in order to retain the gasket.
5. Install the thermostat housing with the heater pipes, heater hoses, gasket and bolts.
6. Install the thermostat housing bolts and tighten to 15 ft. lbs. (20 Nm).
7. Connect the heater hoses to the heater core.
8. Fill the cooling system.

Not sure if you have the 2.7L or the 3.5L so I'll post for both sizes for you:


2.7L Removal procedures

1. Drain cooling system.
   
2. Remove radiator lower hose from thermostat housing.
   
3. Remove nuts from heater tube flange studs.
   
4. Loosen starter bolt at heater tube bracket.
   
5. Pull heater tube out of thermostat housing and position out of the way.
   
6. Remove bolt and two studs.
   
7. Remove thermostat housing, O-ring and thermostat.
   
8. Remove thermostat housing bolts.
   

3.5L Removal procedures

1. Drain cooling system.
   
2. Raise vehicle on hoist.
   
3. Disconnect electrical connectors from engine oil and power steering pressure switches.
   
4. Disconnect radiator and heater hoses from thermostat housing.
   
5. Remove thermostat housing bolts.
   
6. Remove housing, thermostat, and gasket.
   

NOTE:
The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing using a suitable hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing

Hi!!
Engine Coolant Thermostat and Housing Replacement, Tools Required: Hose Clamp Pliers.
Removal Procedure IMPORTANT:Use the hose clamp pliers to gently release tension on the hose clamp until the hose clamp lock feature engages allowing removal of the hose.
Fig. 1: View Of Radiator Inlet & Outlet Hoses

• Drain the cooling system.
• Using the hose clamp pliers, release the tension on the hose clamp at the thermostat housing and reposition the clamp.
• Remove the radiator outlet hose from the thermostat housing.

Fig. 2: Identifying Thermostat Housing & Bolt/Stud

• Remove the thermostat housing bolt/stud.
• Remove the thermostat housing.

INSTALLATION

• Position the thermostat housing.
• Install the thermostat housing bolt/stud.
• Tighten: Tighten the bolts to 25 N.m (18 lb ft).
• Install the radiator outlet hose to the thermostat housing.
• Using a small flat-bladed screwdriver, release the hose clamp retention lock at the thermostat housing.
• Fill the cooling system.

FIG 1

FIG. 2
Good Luck and Merry Christmas!! A HELPFUL - 4 THUMBS - rating for this solution would be greatly appreciated. Thank you for using FixYa.

Two big hoses attach to your radiator. Look for the one that goes back to the TOP of the engine. There is a housing with two bolts in it that the hose connects to. Drain radiator, remove hose. Remove the two bolts. Remove the housing. Thermostat is inside housing or still on engine. It just pulls out. Remove any remaining thermostat housing gasket material from the housing and the engine. Install new thermostat. Should only fit in one way. Install new thermostat housing gasket and the housing. Reattach hose and fill radiator, leaving the cap off. Turn on the car and wait until car gets to warm condition. You will see the water start to move from the radiator to the engine when the new thermostat releases at the proper temperature. Replace the radiator cap and clean up, you are finished.

It is in the rear of the engine by the firewall and the intake manifold will need to be removed to gain access t it.

Engine Coolant Thermostat Replacement (LA3, LY9) Removal Procedure

1. Remove the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement .




2. Complete the following in order to remove the thermostat from the thermostat housing:
2.1. Depress the ears on both sides of the thermostat. 2.2. Rotate the thermostat until it clears the retaining feature of the housing. 2.3. Release the pressure from the thermostat. 2.4. Pull the thermostat from the thermostat housing.

Installation Procedure

1. Complete the following in order to Install the thermostat into the thermostat housing:
1.1. Align the thermostat pin to the thermostat housing orifice. 1.2. Depress the ears on both sides of the thermostat. 1.3. Rotate the thermostat until it aligns with the retaining feature of the housing. 1.4. Release the pressure from the thermostat.
2. Install the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement .

You state that you think you have located the thermostat. The part that will need to be unbolted and removed is the thermostat housing. Simply remove the radiator hose and remove the bolts holding the housing in place. You may need to tap the housing gently to break it loose. The thermostat is located in the housing. Be sure to carefully scrap off any remaining gasket on the thermostat housing and the engine where the housing sits. Replace the thermostat and install a new gasket, replace housing, tighten bolts evenly and reattach radiator hose. Top off the radiator to replace any lost coolant.

300M, Concorde, Intrepid, LHS, 1998-2004 - Thermostat Removal & Installation 2.7L Engine

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
3. Remove radiator lower hose from thermostat housing.
4. Remove nuts from heater tube flange studs.
5. Loosen starter bolt at heater tube bracket.
6. Pull heater tube out of thermostat housing and position out of the way.
7. Remove bolt and two studs.
8. Remove thermostat housing, O-ring and thermostat.
9. Remove thermostat housing bolts.

To install:

1. Clean gasket sealing surfaces.
   NOTE Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.
   
2. Install thermostat and seal into thermostat housing .
3. If removed, install two studs.
4. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
5. Lubricate new heater return tube O-ring with coolant.
6. Position heater return tube flange over two studs. Install nuts.
7. Tighten retaining nuts to 53 inch lbs.(6 Nm).
8. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
9. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
10. Refill cooling system.
11. Inspect for leaks.
12. Connect negative cable.

3.2L & 3.5L Engines

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.


2. Drain cooling system.
3. Raise vehicle on hoist.
4. Disconnect electrical connectors from engine oil and power steering pressure switches.
5. Disconnect radiator and heater hoses from thermostat housing.
6. Remove thermostat housing bolts.
7. Remove housing, thermostat, and gasket.
   NOTE The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing using a suitable hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing.
   

To install:

1. Position gasket on thermostat and housing.
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
3. Install radiator hose.
4. Install bypass hose.
5. Connect electrical connectors from engine oil and power steering pressure switches.
6. Connect negative cable.
7. Fill cooling system.
8. Inspect for leaks.
9. Lower vehicle on hoist.

Hope helps with this (remember rated this) Good luck.

Thermostat replacement on 3.4 liter, Not the thermostat housing is between the Throttle body and exhaust crossover. If you have small haves and the right tools you can remove the two botls without removing the crossover and throttle body. The bottom bolt to the thermostat does not have to come all the way out, there is a cut out on the housing so you can slid it out. Good luck and take your time.

1. Remove the air cleaner and duct assembly.
2. Drain the coolant until the coolant level is below the thermostat.
3. Remove the crossover exhaust pipe.
4. Remove the radiator hose from the thermostat housing.
5. Remove the thermostat housing bolts and clean any sealer from the bolt threads.
6. Remove the thermostat housing and gasket.
7. Remove the thermostat.
8. Install the thermostat.
9. Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
10. Install the radiator hose to the thermostat housing.
11. Install the crossover exhaust pipe.
12. Install the air cleaner and duct assembly.
13. Good luck...
    
14. Fill the cooling system.
15. Install the thermostat housing and gasket.
16. Clean the mating surfaces.

The thermostat is inside a black plastic housing, It is inside the housing assembly where both radiator hoses meet up by the engine. You can't replace just the thermostat, the whole housing has to be replaced,

The 2.7L engine lower radiator hose, connects to the thermostat housing.

To Remove:
1.Disconnect the Negative battery cable.
(Engine COLD!)

1. Drain cooling system.
2. Remove radiator lower hose from thermostat housing.
3. Remove nuts from heater tube flange studs.
4. Loosen starter bolt at heater tube bracket.
5. Pull heater tube out of thermostat housing and position out of the way.
6. Remove bolt and two studs.
7. Remove thermostat housing, O-ring and thermostat.
8. Remove thermostat housing bolts.

To install:
A.Clean gasket sealing surfaces.
B.Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.

1. Install thermostat and seal into thermostat housing .
2. If removed, install two studs.
3. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
4. Lubricate new heater return tube O-ring with coolant.
5. Position heater return tube flange over two studs. Install nuts.
6. Tighten retaining nuts to 53 inch lbs.(6 Nm).
7. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
8. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
9. Refill cooling system.
10. Inspect for leaks.
11. Connect negative cable.

3.2 and 3.5L engines:
Disconnect the battery cable. (Again engine COLD)

1. Drain cooling system.
2. Raise vehicle on hoist.
3. Disconnect electrical connectors from engine oil and power steering pressure switches.
4. Disconnect radiator and heater hoses from thermostat housing.
5. Remove thermostat housing bolts.
6. Remove housing, thermostat, and gasket.

The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing, using a suitable hand held grinder. It is not necessary to restake the replacement thermostat, into the thermostat housing.

To Install:

1. Position gasket on thermostat and housing.
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
3. Install radiator hose.
4. Install bypass hose.
5. Connect electrical connectors from engine oil and power steering pressure switches.
6. Connect negative cable.
7. Fill cooling system.
8. Inspect for leaks.
9. Lower vehicle on hoist.

From AutoZone Repair Guides

I feel this way, I can give you an accurate description, and have taken into account your safety.