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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 55 (Heating, Ventilation, And Air Conditioning System) >> Diagnostic Information and Procedures >> Heating Performance Diagnostic

Heating Performance Diagnostic

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
Step Action Yes No
1 Were you sent here from Symptoms or another diagnostic table? Go to Step 2  Go to Symptoms - HVAC Systems - Manual
2
  1. Start the engine.
  2. Allow the engine to idle.
Does the engine reach a normal operating temperature?		 Go to Step 3  Go to Step 9 
3
    WARNING:

    Refer to Moving Parts and Hot Surfaces Warning .

  1. Allow the engine to idle.
  2. Select the FLOOR mode.
  3. Select the minimum blower speed.
  4. Select the warmest temperature setting.
  5. Feel the temperature of the inlet and outlet heater hoses at the heater core.
Does the inlet heater hose feel warmer than the outlet heater hose?		 Go to Step 7  Go to Step 4 
4
  1. Install a thermometer into the center IP PANEL air outlet.
  2. Secure a thermometer to the heater core outlet hose.
  3. Select the PANEL mode.
  4. Select the maximum blower speed.
  5. Select the warmest temperature setting.
  6. Record the temperature at the following locations:
    • The center IP PANEL air outlet
    • The heater core outlet hose
  7. Compare the recorded temperatures.
Are the two temperature readings about equal?		 Go to Step 5  Go to Step 6 
5
  1. Inspect and repair the following areas of the vehicle for cold air leaks:
    • The cowl
    • The recirculation door
    • The HVAC module case
  2. Perform the necessary repairs.
Are the repairs complete?		 Go to Step 10  -
6
  1. Inspect the temperature door operation. Diagnostic System Check - Vehicle
  2. Perform any necessary repairs.
Are the repairs complete?		 Go to Step 10  -
7
  1. Turn OFF the engine.
  2. Backflush the heater core.
  3. Start the engine.
  4. Select the FLOOR mode.
  5. Select the minimum blower speed.
  6. Select the warmest temperature setting.
  7. Feel the temperature of the inlet and outlet heater hoses at the heater core.
Does the inlet heater hose feel warmer than the outlet heater hose?		 Go to Step 8  Go to Step 10 
8 Replace the heater core. Heater Core Replacement (C60) , or Heater Core Replacement (C42) 
Is the repair complete?		 Go to Step 10  -
9 Repair the low engine temperature concern. Engine Fails To Reach Normal Operating Temperature
Is the repair complete?		 Go to Step 10  -
10 Operate the system in order to verify the repair.
Did you find and correct the condition?		 System OK Go to Step 2 
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