Thermostat or water pump - 2005 Chevrolet Avalanche

i hope this helps for the water pump. The thermostat is located at top of engine simply follow upper hose to engine and remove housing and replace thermostat.

Unfortunately, you can't replace the thermostat by itself. It is part of an overall assembly which includes the waterpump. Below are the instructions:

• Drain the cooling system to a level below the thermostat.
  
• Remove the radiator outlet hose.
  
• Remove the water pump inlet bolts.
  
• Remove the water pump inlet and thermostat from the water pump.
  

To install:

• Install the thermostat and thermostat housing to the water pump.
  
• Install the thermostat housing bolts. Tighten the bolts to 11 ft. lbs. (15 Nm).
  
• Install the radiator outlet hose.
  
• Properly fill the engine cooling system and check for leaks.
  

Hello, here is the instructions for replacing the thermostat. the thermostat is mounted in the water pump

Remove the radiator outlet hose.

Remove the water pump inlet bolts.

Remove the water pump inlet from the water pump.

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.

2.2L Engine To Remove:

1. Drain the cooling system.
2. Remove the exhaust manifold heat shield.
3. Remove or disconnect the following:
4. Thermostat housing to water pump feed pipe
   
5. Remove the thermostat cover bolts from the thermostat housing.
6. Remove and discard the thermostat housing O-ring.
7. Thermostat assembly
   
8. Twist the water feed pipe while pulling to remove it from the water pump. Remove the water pipe from the water pump assembly.
9. Remove and discard the seals from the water pipe.
10. Remove the inner thermostat sleeve.
11. Remove the thermostat assembly.

To Install:

1. Install the thermostat cartridge into the thermostat housing while aligning the cartridge tangs up with the thermostat housing bolt holes. This will assure the inner sleeve can be completely installed.
2. Align and insert the inner sleeve notch into the thermostat housing. If the inner sleeve notch is not properly positioned, the sleeve will not completely seat into the housing.
3. The water feed pipe seals can be slightly lubricated with silicone gel to aid during installation. Install a new O-ring on the water pipe.
4. Position the water pipe into the water pump assembly.
5. Seat the water feed O-ring by pushing and twisting toward the water pump. Take care not to tear or damage the O-ring.
6. Install the thermostat housing cover to the water pipe. The water feed pipe has a locating tab to assure proper alignment.
7. Install a new thermostat housing cover seal into the recess groove.
8. Position the thermostat housing cover into position.
9. Install the thermostat housing cover bolts and tighten bolts to (89 in-lb 10 Nm).
10. Install the exhaust manifold heat shield.
11. Fill the cooling system.

1. Diconnect negative battery cable.

2. If the vehicle has an automate transaxle, remove the exhaust manifold before proceeding with the removal and installation of the thermostat.
3. Drain the cooling system. 4. Take out the bolts that hold the water pump feed pipe to the thermostat housing. 5. Lift out the thermostat-housing-to-water-pump feed pipe. 6. Pull out the thermostat. 7. Set the new thermostat in position. 8. Connect the thermostat housing-to-water-pump feed pipe.
9. Set the bolts in place that holds the thermostat-housing-to-water-pump feed pipe. Torque the bolts to 89 inch pounds. 10. Install the exhaust manifold. 11. Refill the cooling system to the proper level with a 50 / 50 mixture of distilled water / DEX Cool approved coolant. 12. Start the engine and check for leaks. 13. Make the necessary adjustments to coolant levels to assure optimum engine performance.

Please see my tip at http://www.fixya.com/cars/r5929960-s_thermostat . These are generic instructions. Specific instructions from autozone.com for your car are pasted below. If you get stuck, please get back to me.

1. If equipped with an automatic transmission, remove the exhaust manifold.
2. Drain the cooling system.
3. Remove the thermostat housing to water pump feed pipe bolts.

Remove the thermostat housing to water pump feed pipe.

Fig. Remove the thermostat

Remove the thermostat.

To install:

1. Install the thermostat.

Install the thermostat housing to water pump feed pipe.

Fig. Install the thermostat housing to water pump feed pipe

1. Install the thermostat housing to water pump feed pipe bolt and tighten the thermostat housing to water pump feed pipe bolt to 89 lb inches (10 Nm).
2. If equipped with an automatic transmission, install the exhaust manifold.
3. Fill the cooling system.

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.

water pump is behind the timing cover ir runs off your timing belt and the thermostat is in the thermostat housing

1. (This is for a 2.2L engine) If equipped with an automatic transmission, remove the exhaust manifold.
2. Drain the cooling system.
3. Remove the thermostat housing to water pump feed pipe bolts.
4. Remove the thermostat housing to water pump feed pipe.
5. Remove the thermostat.