Thermostat torque spec

Removal & Installation

• 4.6L & 5.4L SOHC ENGINES
• 5.4L & 6.8L ENGINES
• 5.4L DOHC ENGINE
• 6.0L DIESEL ENGINE

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4.6L & 5.4L SOHC Engines

1. Partially drain the engine cooling system to a level below the thermostat.
2. Disconnect the upper radiator hose from the water outlet adapter.
3. Remove the power steering reservoir upper mounting bracket.
4. Remove the bolts and remove the water outlet adapter.
5. Remove the water thermostat and the O-ring seal. Discard the O-ring seal.
6. Installation is the reverse of the removal procedure. Tighten the water outlet adapter bolts to 18 ft. lbs. (25 Nm). Tighten the power steering reservoir upper mounting bracket as shown in the accompanying illustration.
   
   

   Fig. View of the power steering reservoir upper mounting bracket and tightening specifications
   
   
   

   Fig. Exploded view of the water outlet adapter and tightening specifications
   

5.4L & 6.8L Engines

1. Partially drain the cooling system to a level below the thermostat.
2. Disconnect the upper radiator hose.
3. Remove the coolant outlet connection, as follows:
   1. Remove the bolts.
   2. Remove the coolant outlet connection.
   
   
4. Remove the (A) coolant thermostat and the (B) O-ring seal.
5. Discard the (B) O-ring seal.
   
   

   Fig. Remove the (A) coolant thermostat and the (B) O-ring seal
   

To install:

NOTE Thermostat must be installed as illustrated.

1. Use a new (A) O-ring seal to position the (B) coolant thermostat in the (C) upper intake manifold.
   
   

   Fig. Use a new (A) O-ring seal to position the (B) coolant thermostat in the (C) upper intake manifold
   

2. Install the coolant outlet connection, as follows:
   1. Position the coolant outlet connection on the upper intake manifold.
   2. Install the bolts and tighten to 15-22 ft. lbs. (20-30 Nm).
   
   
3. Connect the upper radiator hose.
4. Fill the cooling system.

1. Before servicing the vehicle, refer to the precautions section.
2. Partially drain the cooling system to a level below the thermostat.
3. Disconnect the upper radiator hose.
4. Remove the coolant outlet connection, as follows:
   1. Remove the bolts.
   2. Remove the coolant outlet connection.
   
   
5. Remove the (A) coolant thermostat and the (B) O-ring seal.
6. Discard the (B) O-ring seal.
   
   

   Fig. Remove the (A) coolant thermostat and the (B) O-ring seal
   

To install:

NOTE Thermostat must be installed as illustrated.

1. Use a new (A) O-ring seal to position the (B) coolant thermostat in the (C) upper intake manifold.
   
   

   Fig. Use a new (A) O-ring seal to position the (B) coolant thermostat in the (C) upper intake manifold
   

2. Install the coolant outlet connection, as follows:
   1. Position the coolant outlet connection on the upper intake manifold.
   2. Install the bolts and tighten to 15-22 ft. lbs. (20-30 Nm).
   
   
3. Connect the upper radiator hose.
4. Fill the cooling system.

5.4L DOHC Engine

1. Partially drain the engine cooling system to a level below the thermostat.
2. Disconnect the upper radiator hose, the heater water inlet hose and the heated PCV inlet hose from the water outlet adapter.
   
   

   Fig. Disconnect the upper radiator hose, the heater water inlet hose and the heated PCV inlet hose from the water outlet adapter
   

3. Remove the water hose connection and thermostat.
4. Installation is the reverse of the removal procedure. Tighten the mounting bolt to 18 ft. lbs. (25 Nm).
   
   

   Fig. Exploded view of the thermostat-5.4L DOHC engine
   

Hello rev7, this is an easy job on the 4.3 litre engine.

Drain some of the engine coolant by placing a bucket under the radiator and open the petcock (the plastic bolt facing the engine) located on the bottom of the radiator. Empty the coolant from the radiator until the radiator is about half full.

Remove the air intake, hose and the coolant neck (outlet) bolts using a ratchet and & 13 mm socket. Remove the outlet from the intake manifold. Take note of the direction the thermostat is seated and then remove the thermostat from the housing.
Clean the remains of the old gasket or sealer from the housing and outlet. Install the thermostat and gasket to the intake manifold in the same direction it was seated before removal. Put a thin layer of silicone on the water outlet surface. Install the outlet before the silicone dries

Install the water outlet bolts. Tighten the bolts to 18 foot pounds
Filll the radiator completely and check for any leaks. Install the radiator cap. Install the air cleaner inlet hose. Start the engine and turn the heater on with the blower on high & run the engine until the thermostat opens. The top radiator hose will be hot when the thermostat opens.

Turn off the vehicle and allow the engine to cool. Check fluid level and add more antifreeze if needed.....Good luck & hope this helps.

Try this:

3.0L DOHC Engine

1. Drain the coolant until the level of the coolant is below the level of the thermostat.
2. Raise the vehicle and support it with jackstands.
3. Disconnect the lower radiator hose from the water inlet connection.
4. Unfasten the two water inlet connection retaining bolts and remove the water inlet connection.
5. Remove the O-ring seal and thermostat from the water inlet connection. Inspect the O-ring for damage and replace as necessary.

To install:

1. Clean the water inlet connection mating surfaces.
2. Install the O-ring, thermostat and the water inlet connection. Refer to the accompanying illustration If you can-t remember how the O-ring and thermostat are positioned.
3. Install the water inlet connection assembly retainers and tighten them to 71-106 inch lbs. (8-12 Nm).
4. Connect the lower radiator hose to the water inlet connection.
5. Fill the engine with coolant, start the engine and check for leaks.
6. Stop the engine and top off the coolant recovery reservoir as necessary.
   
   

   Fig. Exploded view of the water inlet connection and the thermostat assembly-3.0L DOHC engines
   

3.0L OHV Engine

1. Drain the coolant until the level of the coolant is below the level of the thermostat.
2. Disconnect the upper radiator hose from the water hose connection.
3. Unfasten the three water inlet connection retaining bolts and remove the water hose connection.
4. Remove the gasket and thermostat from the water hose connection. Discard the gasket.

To install:

1. Clean the water inlet connection mating surfaces.
   NOTE The jiggle valve on the thermostat must be in the up position.
   
2. Place the thermostat in the water hose connection making sure the thermostat jiggle valve is facing up.
3. Install the new gasket and place the water hose connection assembly into position.
4. Install the water hose connection assembly retainers and tighten them to 89-124 inch lbs. (10-14 Nm).
5. Connect the upper radiator hose to the water hose connection.
6. Fill the engine with coolant, start the engine and check for leaks.
7. Stop the engine and top off the coolant recovery reservoir as necessary.
   
   

   Fig. Exploded view of the water hose connection and the thermostat assembly-3.0L OHV engines
   
   
   

   Fig. Remove the upper radiator hose from the water outlet
   
   
   

   Fig. Remove the water outlet retaining bolts and . . .
   
   
   

   Fig. . . . remove the outlet from the engine
   
   
   

   Fig. Remove the thermostat from the water outlet
   
   
   

   Fig. Inspect the water outlet connection for cracks or damage
   
   
   

   Fig. Thoroughly clean the mating surfaces of the water outlet and . . .
   
   
   

   Fig. . . . the engine before installing a new gasket
   
   
   

   Fig. The jiggle valve must be in the up (12 o-clock) position after installation into the water outlet
   

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.

Thermostat Removal & Installation 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.

8.1L Engines 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, 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.

GM Cavalier/Sunfire 1995-2000 Repair Guide

Thermostat - REMOVAL & INSTALLATION

2.2L Engine
(see Figures 1, 2, 3, 4, 5 and 6)


Fig. 1: The thermostat is located in the lower radiator hose on the 2.2L engine


Fig. 2: Remove the two retaining bolts for on the housing


Fig. 3: Separate the housing halves to access the thermostat


Fig. 4: Pull the thermostat out to remove it from the housing


Fig. 5: The thermostat has an O-ring which goes around the center


Fig. 6: Thoroughly clean the mating surfaces of the thermostat housing
When adding coolant, it is important that you use GM Goodwrench DEX-COOL® (orange colored, silicate free) coolant meeting GM specifications. On these vehicles, if silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner; at 30,000 miles or 24 months.

1. Disconnect the negative battery cable.
2. Properly drain and recover the coolant until the level is below the thermostat.
3. Unfasten the coolant outlet-to-inlet manifold attaching bolt and nut, then remove the outlet.
4. Remove the thermostat. Clean the inlet manifold and outlet mating surfaces.

To install:

1. Install a new O-ring onto the thermostat
2. Place the thermostat in the inlet manifold.
3. Attach the coolant outlet to the inlet manifold, using the bolt and nut. Tighten to 89 inch lbs. (10 Nm).
4. Refill the engine cooling system.
5. Connect the negative battery cable, then start the engine and check for coolant leaks.

Hope this helped (remember comment and rated this).

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.

yes the entire idler arm needs replacement to clear this problem.
there are many things to be checked
just click this link directly
http://www.2carpros.com/maintenance/car_safety_inspection.htm
you will need to remove the alternator to replace the idler arm pulley
Disconnect the negative, then the positive battery cables.
Remove the battery from the vehicle.
Remove the battery tray using the following procedure:
Remove the four battery tray bolts.
Remove the battery tray from the vehicle.
Remove the serpentine drive belt.
Remove the cooling fan assembly using the following procedure:
Remove the wishbone-shaped engine mount strut by removing the bolts and nuts at the engine mount bracket and on the upper radiator support.
Remove the strut from the vehicle.
Disconnect the cooling fan harness from the engine wiring harness.
Reposition the wiring harness at the upper radiator support.
Remove the cooling fan shroud bolts.
Remove the right side radiator bracket.
Remove the cooling fan shroud with the electric cooling fan motors and fans as an assembly.
Remove the thermostat housing and the radiator hose using the following procedure.
Partially drain the engine coolant.
Use hose clamp pliers to remove the radiator hose clamp to the water inlet housing and disconnect the radiator hose.
Use hose clamp pliers to remove the heater hose clamp to the water inlet housing and disconnect the heater hose from the water inlet housing.
Use hose clamp pliers to remove the surge tank inlet hose clamp from the water inlet housing and disconnect the surge tank hose from the water inlet housing.
Remove the water inlet housing bolts and remove the water inlet housing.
Remove the outboard generator bolt and loosen the inboard bolt.
Remove the idler pulley bolt and idler pulley.
Unplug the electrical connector from the alternator.
Pull back the protective boot from the alternator "BAT" terminal, remove the nut and disconnect the heavy "BAT" wire from the alternator terminal stud.
Remove the alternator from the vehicle.
To Install:
Position the alternator to the engine.
Plug in the electrical connectors and install the heavy "BAT" wire to the alternator terminal stud. Tighten the nut to 15 ft. lbs. (20 Nm). Press the protective boot back in place over the stud terminal and nut assembly.
Install the outboard alternator bolt into the alternator housing.
Install the inboard alternator bolt and then finger-tighten the outboard bolt.
Install the idler pulley and idler pulley bolt.
Tighten the bolts in the following torque sequence:
Tighten the idler pulley bolt to 37 ft lbs. (50 Nm).
Tighten the alternator bolts to 37 ft. lbs. (50 Nm).
Install the water inlet and thermostat housing and the radiator hose, observing the following:
Inspect and clean the mating surfaces on the thermostat cover and its mounting surface on the engine.
Use RTV Sealer GM #1052366 or equivalent on the mounting bolts since the threaded openings are open to the cooling system and the torque requirement is low.
Install the water inlet and thermostat housing and tighten the bolts to 80 inch lbs. (9 Nm).
Connect the surge tank inlet hose to the water inlet housing.
Connect the heater hose to the water inlet housing.
Connect the radiator hose to the water inlet housing.
Install the cooling fan assembly and tighten the radiator bracket bolts to 80 inch lbs. (9 Nm). Plug in the wiring harness at the upper radiator support. Plug in the cooling fan wiring harness to the engine wiring harness.
Install the engine mount strut bracket to the upper radiator support first, insert the through bolt. Attach the engine side of the strut to the engine mount strut bracket on the engine and install the through bolt. Thread the nuts on the through bolts and tighten to 35 ft. lbs. (48 Nm).
Install the battery tray and tighten the bolts to 44 inch lbs. (5 Nm).
Install the battery.
Install the serpentine drive belt.
Connect the positive, then the negative battery cables.
This will help. Thanks please keep updated. please do rate the solution positively .thank you for using fixya.

Exploded view of the thermostat arrangement—3.8L engines

The thermostat is located in the thermostat housing, which is mounted to the coolant crossover tube. The bypass hose is connected to the thermostat water inlet on one end, and to the intake manifold water outlet on the other. The thermostat is not located in the intake manifold water outlet, where the upper radiator hose is connected.

1. Drain the radiator and recycle the engine coolant.
2. Remove the upper radiator hose bracket bolt and remove the bracket.
3. On 1993-98 3.0L engine models:
   1. Remove the bolt from the A/C high pressure line bracket at the front of the engine.
   2. Remove the two A/C accumulator/drier bracket bolts.
   3. Position the accumulator/drier and A/C line out of the way.
   
   
4. Remove the bypass hose clamp and remove the hose from the water inlet.
5. Remove the four water inlet bolts and remove the inlet.
6. Remove the thermostat from the inlet.

To install:

1. Clean and dry the water inlet and thermostat housing mating surfaces.
2. Apply a continuous bead of RTV silicone sealant 0.08-0.12 inch (2.0-3.0mm) wide to the water inlet mating surface.

NOTE The water inlet must be installed within 5 minutes of applying the sealant.

1. Install the thermostat in the water inlet, with the jiggle valve at the topmost (12 o'clock) position.
2. Install the water inlet to the thermostat housing. Install the bolts and tighten them to 12-15 ft. lbs. (16-21 Nm).
3. Install the bypass hose to the water inlet, using a new clamp.
4. On 1993-98 3.0L engine models:
   1. Install the accumulator/drier and tighten the bracket bolts to 45 inch lbs. (5 Nm).
   2. Install the A/C high pressure line bracket and tighten the bolt to 45 inch lbs. (5 Nm).
   3. Install the upper radiator hose bracket and tighten the bolt to 34-48 ft. lbs. (46-65 Nm).
   
   

NOTE Allow the sealant to dry for at least 30 minutes before adding coolant.

1. Fill the cooling system. Run the engine and check for leaks.