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Home >> Pontiac >> 2001 >> Aztek Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 53 (HVAC Systems - Automatic) >> Performance Test >> Heater Performance Test
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Heater Performance Test

WARNING: This page is about a different car, the 2002 Pontiac Aztek and 2002 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
  1. Were you sent here from SYMPTOM TESTS or another diagnostic table? If so, go to next step. If not, go to TROUBLESHOOTING  .
  2. Start the engine. Allow the engine to idle. Does the engine reach a normal operating temperature? If so, go to next step. If not, go to step  9 .
  3. Allow the engine to idle. Select the FLOOR mode. Select the minimum blower speed. Select the warmest temperature setting. 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? If so, go to step  7 . If not, go to next step.
  4. Install a thermometer into the center I/P panel air outlet. Secure a thermometer to the heater core outlet hose. Select the PANEL mode. Select the maximum blower speed. Select the warmest temperature setting. Record the temperature at the center I/P panel air outlet and the heater core outlet hose. Compare the recorded temperatures. Are the 2 temperature readings about equal? If so, go to next step. If not, go to step  6 .
  5. Inspect and repair the cowl, the recirculation door and the HVAC module case of the vehicle for cold air leaks. After repairs are complete, go to step  10 .
  6. Inspect the temperature door operation. Perform any necessary repairs. After repairs are complete, go to step  10 .
  7. Turn engine off. Back-flush the heater core. Start the engine. Select the FLOOR mode. Select the minimum blower speed. Select the warmest temperature setting. 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? If so, go to step  8 . If not, go to step  10 .
  8. Replace the heater core. See HEATER CORE  under REMOVAL & INSTALLATION. After repairs are complete, go to step  10 .
  9. Repair the low engine temperature concern. After repairs are complete, go to next step.
  10. Operate the system in order to verify the repair. Did you find and correct the condition? If so, system okay. If not, go to step  2 .
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