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Q: other than the fan and heater core what could cause little or no hot air blowing on 1991 Cadillac Seville

The heater fan works but does not blow hot air when the heater is on. Warmer air does seem to seep into the cabin.
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Poor heat. Good air flow and all modes work. The temperature door moves to full hot. 180 degrees at each heater hose. Flushed the heater core-the same.


1. Remove the heater core and check for cool areas on the core by hand or with a temperature gun.

2. Replace the heater core if the core is not hot at all areas.

3. With the heater core removed, check the temperature door and see if it is in the full hot position.

Replace your heater core. It has a restriction.
FIRST be sure it is FULL of coolant!! Next, possible thermostat stuck open. I do not know if this one has a heater flow control valve or not but check with parts store anyway.
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