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Engine Cooling System: Maintenance GMC Envoy II

Cooling System (Mechanical) ~492 words

Draining Procedure

  1. Park the vehicle on a level surface.
  2. Allow the engine to cool.
  3. Remove the radiator cap.
  4. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-200385-S41061932852005102000000) in General Information.
  5. Place a drain pan under the lower radiator hose connection at the bottom of the radiator.
  6. Using J 38185 slide the hose clamp back on the hose.
  7. Slowly remove the lower radiator hose and drain the coolant into the drain pan.
  8. Inspect the engine coolant for the following conditions: Discolored appearance-Follow the flush procedure. Refer to «Flushing»(ref-200409-S21819518542005102000000) . Normal in appearance-Follow the filling procedure. If a complete block drain is required, remove the plug located on the LH side of the block.

Draining and Filling Cooling System (LM4)

Tools Required

  1. J 38185 Hose Clamp Pliers
  2. J 26568 Coolant and Battery Fluid Tester. See «Special Tools»(ref-200409-S17093269022005102000000) .
  1. Park the vehicle on a level surface.
  2. Allow the engine to cool.
  3. Using J 38185 slide the coolant air bleed hose clamp back on to the hose.
  4. Remove the coolant air bleed hose from the throttle body.
  5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-200385-S41061932852005102000000) in General Information.
  6. Place a drain pan under the lower radiator hose connection at the bottom of the radiator.
  7. Using J 38185 slide the hose clamp back on the hose.
  8. Slowly remove the lower radiator hose and drain the coolant into the drain pan.
  9. Inspect the engine coolant for the following conditions: Discolored appearance-Follow the flush procedure. Refer to «Flushing»(ref-200409-S21819518542005102000000) . Normal in appearance-Follow the filling procedure. If a complete block drain is required, remove the coolant heater or plug located on the LH side of the block. Refer to «Coolant Heater Replacement (LL8)»(ref-200409-S15674786282005102000000) or «Coolant Heater Replacement (LM4)»(ref-200409-S16010780652005102000000) .
  10. Remove the radiator cap.

Flushing

IMPORTANTDo not use a chemical flush. Store used coolant in the proper manner, such as in a used engine coolant holding tank. Do not pour used coolant down a drain. Ethylene glycol antifreeze is a very toxic chemical. Do not dispose of coolant into the sewer system or ground water. This is illegal and ecologically unsound. Various methods and equipment can be used to flush the cooling system. If special equipment is used, such as a back flusher, follow the manufacturer's instruction. Always remove the thermostat before flushing the cooling system.

When the cooling system becomes contaminated, the cooling system should be flushed thoroughly to remove the contaminants before the engine is seriously damaged.

  1. Drain the cooling system. Refer to «Draining and Filling Cooling System (LL8)»(ref-200409-S40000666192005102000000) or «Draining and Filling Cooling System (LM4)»(ref-200409-S00791831952005102000000) .
  2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(ref-200409-S19424745182005102000000) .
  3. Clean and flush the coolant recovery reservoir with clean, drinkable water.
  4. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(ref-200409-S19424745182005102000000) .
  5. Remove the thermostat. Refer to «Thermostat Replacement (4.2L Engine)»(ref-200409-S15598541522005102000000) or «Thermostat Replacement (5.3L Engine)»(ref-200409-S34581073262005102000000) .
  6. Follow the drain and fill procedure using only clean, drinkable water. Refer to «Draining and Filling Cooling System (LL8)»(ref-200409-S40000666192005102000000) or «Draining and Filling Cooling System (LM4)»(ref-200409-S00791831952005102000000) .
  7. Run the engine for 20 minutes.
  8. Stop the engine.
  9. Drain the cooling system. Refer to «Draining and Filling Cooling System (LL8)»(ref-200409-S40000666192005102000000) or «Draining and Filling Cooling System (LM4)»(ref-200409-S00791831952005102000000) .
  10. Repeat the procedure if necessary, until the fluid is nearly colorless.
  11. Install the thermostat. Refer to «Thermostat Replacement (4.2L Engine)»(ref-200409-S15598541522005102000000) or «Thermostat Replacement (5.3L Engine)»(ref-200409-S34581073262005102000000) .
  12. Fill the cooling system. Refer to «Draining and Filling Cooling System (LL8)»(ref-200409-S40000666192005102000000) or «Draining and Filling Cooling System (LM4)»(ref-200409-S00791831952005102000000) .

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