T'stat torquing on Ranger 2.9 liter engine

4.8L, 5.3L and 6.0L Engines To Remove:
CAUTION
The thermostat is not serviceable separately. The thermostat housing (water pump inlet) and thermostat must be replaced as an assembly.

1. Remove the radiator outlet hose.
   
   
2. Remove the bolts from water pump inlet.
3. Remove the water pump inlet from the water pump.

To Install:

1. Install the water pump inlet to the water pump.
2. Install the water pump inlet bolts.
   • Torque to: 11 ft-lbs. (15 Nm)
3. Install the radiator outlet hose.

6.6L Engine To Remove:

1. Before servicing the vehicle refer to the precautions at the beginning of this section.
2. Drain the engine coolant.
3. Remove or disconnect the following:
   • Water outlet 6.6L Thermostat housing removal
     
     
   • Bolt for the fuel line bracket
   • Thermostat housing cover bolts
   • Thermostats and seals

To Install:
6.6L Thermostats and seals

1. Install or connect the following:
   • Thermostats and seals to the thermostat housing NOTE: The rear thermostat (D) has 2 vent valves. Install with the vent valves towards the rear of engine.
     
   • Thermostat housing cover with a NEW gasket
   • Thermostat housing cover bolts and tighten the bolts
     1. Torque to: 15 ft. lbs. (21 Nm)
   • Fuel line bracket bolt and tighten the bolt
     1. Torque to: 15 ft. lbs. (21 Nm)
   • Water outlet
2. Fill the engine with coolant.
3. Test drive the vehicle to confirm the repairs.

8.1L Engine To Remove:

1. Before servicing the vehicle refer to the precautions at the beginning of this section.
2. Drain the cooling system.
3. Remove or disconnect the following:
   • Inlet hose from the water outlet Water outlet and thermostat removal
     
     
   • Water outlet bolts (B)
   • Water outlet (A)
   • Thermostat (C)

To Install:

1. Install or connect the following:
   • Thermostat
   • Water outlet
   • Water outlet bolts and tighten the bolts.
     1. Torque to: 22 ft-lbs (30 Nm)
   • Inlet hose to the water outlet
2. Fill the cooling system.
3. Test drive the vehicle to confirm the repairs.

Removal & Installation 3.0L Engine To Remove:

1. Before servicing the vehicle, refer to the precautions in the beginning of this section
2. Drain the engine cooling system
3. Remove or disconnect the following:
   • Air cleaner outlet tube
   • Hoses and remove the thermostat housing assembly
   • Bolts separate the housing and remove the thermostat and seal

To Install:

1. Install or connect the following:
   • New seal and thermostat. Torque bolts to 8 ft-lbs (11 Nm)
   • Hoses to assembly
   • Air cleaner outlet tube

3.9L Engine To Remove:

1. Before servicing the vehicle, refer to the precautions in the beginning of this section
2. Drain the engine cooling system
3. Remove or disconnect the following:
   • Intake manifold
   • Nuts and remove the hose bracket
   • Stud bolts
   • Lower radiator hose from the thermostat housing
   • Bolts and thermostat housing cover
   • Thermostat and seal

To Install:

1. Install or connect the following:
   • New seal and thermostat
   • Housing cover. Torque bolts to 8 ft-lbs (11 Nm)
   • Lower radiator hose to the thermostat housing
   • Stud bolts. Torque to 10 ft-lbs (13 Nm)
   • Hose bracket. Torque nuts to 89 in-lbs (10 Nm)
   • Intake manifold

Crankshaft Position Sensor Replacement - Removal Procedure

1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
3. Remove the starter motor. Refer to Starter Motor Replacement in Engine Electrical.
4. Disconnect the crankshaft position (CKP) sensor electrical connector.
5. Remove the CKP sensor bolt (1).
6. Remove the CKP sensor (2) from the engine block:
• Remove the sensor by pulling on the sensor connector. DO NOT pry on the bracket.
• DO NOT rotate or twist the sensor or damage the mounting bracket if the sensor is being reused.

Installation Procedure

Important: When replacing the CKP sensor with a new sensor or reinstalling the original sensor, use the following recommended procedures:
• Ensure that the CKP sensor bore is completely free of any foreign material, such as old O-ring, dirt, burrs, etc.
• Ensure that the flange on the CKP sensor bore is not damaged.
• Clean all the mounting surfaces before re-installing any components.
• Inspect the CKP sensor and replace the sensor if any of the following conditions are present:
- The bracket is damaged.
- The bottom of the brass housing exhibits any damage.
- Never install a sensor that has been dropped.
• Lubricate the O-ring on the sensor with clean engine oil prior to installing the sensor .
• Inspect all the connectors for any damaged terminals.

1. Install and fully seat the CKP sensor (2) into the engine block.
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the CKP sensor bolt (1).
Tighten
Tighten the bolt to 9 N·m (80 lb in)
3. Ensure that the CKP sensor mounting flange is contacting the engine block.
4. Connect the CKP sensor electrical connector.
5. Install the starter motor. Refer to Starter Motor Replacement in Engine Electrical.
6. Connect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
7. Lower the vehicle.
8. The CKP System Variation Learn Procedure must be performed after replacing the CKP sensor. Even if the original sensor is reinstalled, the Learn Procedure must be performed.
9. Engine Coolant Temperature Sensor Replacement
Removal Procedure
Notice: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
1. Partially drain the cooling system. Refer to Draining and Filling Cooling System in Engine Cooling.
2. Remove the exhaust gas recirculation (EGR) inlet pipe. Refer to Exhaust Gas Recirculation (EGR) Inlet Pipe Replacement .
3. Disconnect the ECT sensor (1) .
4. Remove the ECT sensor.

Installation Procedure
Notice: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
Notice: Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.

1. Coat the sensor threads with sealer GM P/N 12346004, (Canadian P/N 10953480) or equivalent.
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the ECT sensor (1).
Tighten
Tighten the sensor to 20 N·m (15 lb ft).
3. Connect the ECT sensor electrical connector.
4. Install the EGR inlet pipe. Refer to Exhaust Gas Recirculation (EGR) Inlet Pipe Replacement .
5. Fill the cooling system. Refer to Draining and Filling Cooling System in Engine Cooling.
6. Engine Coolant Thermostat Replacement
Tools Required
J 38185 Hose Clamp Pliers

Removal Procedure
1. Partially drain the cooling system. Refer to Cooling

System Draining and Filling .
2. Use the J 38185 to remove the radiator hose clamp from the water inlet housing.
3. Remove the radiator hose from the water inlet housing.
4. Use the J 38185 to remove the heater hose clamp from the water inlet housing.
5. Remove the heater hose from the water inlet housing.
6. Use the J 38185 to remove the surge tank inlet hose clamp from the water inlet housing.
7. Remove the surge tank inlet hose from the water inlet housing.
8. Remove the water inlet housing bolts.
Important: The water inlet housing (2) and the thermostat are replaced as an assembly.
9. Remove the water inlet housing and the thermostat.
10. Inspect and clean the water inlet mating surfaces.

Installation Procedure

1. Install the thermostat and the water inlet housing (2).
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the water inlet housing bolts.
Tighten
Tighten the bolts to 9 N·m (80 lb in).
3. Install the surge tank inlet hose to the water inlet housing.
4. Use theJ 38185 to install the surge tank hose clamp to the water inlet housing.
5. Install the heater hose to the water inlet housing.
6. Use theJ 38185 to install the heater hose clamp to the water inlet housing.
7. Install the radiator hose to the water inlet housing.
8. Use theJ 38185 to install the radiator hose clamp to the water inlet housing.
9. Fill the cooling system. Refer to Cooling System Draining and Filling

Time Estimated: 4.5 hours.

Hope helps.

It Depends on which engine you have, this is how it goes for both. I use a little RTV with a new ring as well.

THERMOSTAT REPLACEMENT (4.2L ENGINE)
Removal Procedure
1. Remove the necessary coolant from the radiator.
2. Remove the generator.
3. Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
4. Remove the thermostat housing bolts.
5. Remove the thermostat housing from the engine block.
6. Clean all of the surfaces of the thermostat housing.
7. Clean the sealing surface of the engine block.
Installation Procedure
1. Install the thermostat housing to the engine block.
2. Install the thermostat housing bolts.
Tighten: Tighten the bolts to 10 N.m (89 lb in).
3. Lubricate the inner diameter of the radiator hose with engine coolant.
4. Install the outlet hose to the thermostat housing. Secure the hose with the clamp.
5. Install the generator.
6. Fill the cooling system with specified coolant and concentration. Follow the correct cooling systen bleed procedure for your engine.
7. Inspect all sealing surfaces for leaks after starting the engine.
THERMOSTAT REPLACEMENT (5.3L ENGINE)
1. Drain Radiator and remove the radiator outlet hose.
2. Remove the water pump inlet bolts.
3. Remove the water pump inlet and thermostat from the water pump.
Installation Procedure
IMPORTANT: The thermostat is not serviceable separately. The water pump inlet and thermostat must be replaced as an assembly.
1. Install the thermostat and thermostat housing to the water pump.
2. Install the thermostat housing bolts.15 N.m
3. Install the radiator outlet hose.
4. Fill the cooling system with specified coolant and concentration. Follow the correct cooling systen bleed procedure for your engine.
5. Inspect all sealing surfaces for leaks after starting the engine.

Check out the diagram:


The removal of the thermostat from its housing on the 4.0L engine

To install:

1. Install the replacement thermostat so that the pellet, which is encircled by a coil spring, faces the engine. All thermostats are marked on the outer flange to indicate the proper installed position.
   
2. Observe the recess groove in the engine cylinder head .
   
3. Position thermostat into this groove with arrow and air bleed hole on outer flange pointing up.
   
4. Install replacement gasket and thermostat housing
   
   CAUTION Tightening the thermostat housing unevenly or with the thermostat out of its recess may result in a cracked housing.
   
   
5. Tighten the housing bolts to 15 ft. lbs. (20 Nm) torque.
   
6. Install hoses to thermostat housing.
   
7. Install electrical connector to coolant temperature sensor.
   
8. Be sure that the radiator draincock is tightly closed. Fill the cooling system.
   
9. Start and warm the engine. Check for leaks
   

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.