How to get the thermostat housing to disconnect. We have taken all bolts loose but will not come apart.

Check this procedure for...
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 (remember to rate and comment thius answer).

Hi, the first part is data taken along with the code. The code P1281 indicates the engine is running cold (141 degrees--should be at least 190). Is your temp gage running lower than you are used to? If yes, it may be your thermostat has failed open. I have pasted below instructions for replacing the thermostat. Please let me know if you have any questions, and thanks for using FixYa.

3.7L & 4.7L Engines WARNING Do not loosen radiator drain **** with system hot and pressurized. Serious burns from coolant can occur.


NOTE Do not waste reusable coolant. If solution is clean, drain coolant into a clean container for reuse. If thermostat is being replaced, be sure that replacement is specified thermostat for vehicle model and engine type.

1. Disconnect negative battery cable at battery.
2. Drain cooling system.
3. Raise vehicle on hoist.
4. Remove splash shield.
5. Remove lower radiator hose clamp and lower radiator hose at thermostat housing.
6. Remove thermostat housing mounting bolts, thermostat housing and thermostat.

To install:

1. Clean mating areas of timing chain cover and thermostat housing.
2. Install thermostat (spring side down) into recessed machined groove on timing chain cover.
3. Position thermostat housing on timing chain cover.
4. Install two housing-to-timing chain cover bolts. Tighten bolts to 115 inch lbs. (13 Nm).
   CAUTION Housing must be tightened evenly and thermostat must be centered into recessed groove in timing chain cover. If not, it may result in a cracked housing, damaged timing chain cover threads or coolant leaks.
   
5. Install lower radiator hose on thermostat housing.
6. Install splash shield.
7. Lower vehicle.
8. Fill cooling system.
9. Connect negative battery cable to battery.
10. Start and warm the engine. Check for leaks.

Removal & Installation, 4.0 liter engine

1. Disconnect the negative battery cable.
2. If necessary, disconnect the coolant temperature sensor electrical connector.
3. Disconnect the upper radiator hose from the thermostat housing.
4. Remove the attaching bolts and lift the housing from the engine.

Remove the thermostat and gasket.
To install:

1. Clean all gasket surfaces thoroughly.
2. Place the thermostat in the housing with the spring inside the engine.
3. Install a new gasket with a small amount of sealing compound applied to both sides.
4. Install the water outlet and tighten the mounting bolts to 200 inch lbs. (23 Nm) on V-8 engines and 15 ft. lbs. (20 Nm) on non-8 cylinder engines.
5. Install the upper radiator hose to the housing and tighten the hose clamp.
6. Connect the coolant temperature sensor connector to the housing.
7. Refill the cooling system.

Hi.

Here summary procedure:

Disconnect the battery ground cable and set it apart.
Bleed coolant fluid.
Follow the upper radiator hose until you reach the thermostat housing.
Undo coolant hose from housing.
Undo the bolts holding the housing.
Remove thermostat.
Replace gasket.
Refit the thermostat.

Here a forum showing more details and pictures. Click here to open.

Regards.

Ginko

Follow the upper radiator hose from the radiator to the engine. The hose will be attached to the thermostat housing which is fastened to the engine with two bolts. While the engine is cold, remove these two bolts and lift up the housing to expose the thermostat. Replace the old thermostat with a new one. An auto parts store employee can help you purchase the correct thermostat for your particular application. When you install the new thermostat, be sure to use the rubber gasket that comes with it. Make sure you don't put the new thermostat in upside down. Sounds silly, but it does happen. Bolt the housing back down, careful not to over tighten the bolts since they most likely will be going into aluminum. Replace any antifreeze that may have been lost with a 50/50 solution of antifreeze and water. You can buy this already premixed by the gallon wherever you buy the thermostat.

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 this help (remember comment and rated this).

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.

On the 4 cylinder 2.0 L the thermostat is located where the upper Radiator hose and the recovery tank hose connect to the housing on the block. Disconnect the Neg (-) (Black) terminal. Drain and recycle the coolant, remove the air intake resonator, the recovery and upper hoses. remove the three bolts to the housing, remove the thermostat and )-ring (important, replace the O ring with your new thermostat. re assemble as you have taken apart. tork the bolts to 71-97 inch lbs on the 6 cylinder 2.5 L the process is similar, except there are only two bolts on the housing, tork the bolts after you have installed the new one to 15-22 ft lbs. I hope this solves your issue, thanks

In most circumstances, the thermostat is located in a housing on the engine where the upper radiator hose connects, on the dodge 3.7 and 4.7, the thermostat is located on the engine where the lower radiator hose connects to the engine. disconnect the Negative battery terminal (black side) drain coolant, on most of the V-6 and V-8 models, you will need to remove or reposition the alternator. disconnect any sensors connected to the housing, remove the retaining bolts, note which one comes out from which hole (different length bolts), note how the thermostat sat in, install new one and re assemble as you have taken apart, Good Luck! if you need more info go to autozone.com and register, you can access the free online manuals, you will need to provide info about your vehicle, engine size, etc...
3.7 and 4.7 motor photos courtesy of autozone.com

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.

Follow the upper radiator hose back to the engine block. There will be a cover plate with bolts holding it to a housing. This housing contains the thermostat. It has to be taken apart with the 2 possibly 3 bolts and a gasket. A LOT of fluid will pour out when you break the seal and open it. It maybe very difficult to get out without special tools to get to the bolts. You will then need to reseal it with rtv or supplied gaskets.