1999 Ford Taurus heater intermittant blowing hot air to col

1999 FORD TAURUS
120,000 MILES • 6 CYL • FWD • AUTOMATIC
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CUNN425
  • MEMBER
  • 1 POST
Heater is not working all the time. We checked the hoses and radiator level. replaced a T valve that seemed to be blocked, Replaced the thermostat.
Heat will run hot and them go cold, turn it off and back on and it will do the same. AC was also running when the problems was going on. We had to disconnect it for the winter.
Son is an auto mechanic with 30 some odd years in the trade but is stumped. Some one told me about a unit in the heater, he said it could be a "defibulator"
Feb 16, 2009 at 8:18 AM
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BMRFIXIT
  • ✓Experienced Mechanic
  • 19,053 POSTS
Very common for the heater core to be clogged
where it will allow small amount of hot coolant in not enough to keep warm
air coming

ask him to check heater core hoses under the hood when engine warm
both hoses should be hot
and if so then its the blend door actuator under the dash in the HVAC box
if one hot and the other warm or cold
you have a clogged heater core and need to be isolated and flushed
(very ,very common )
good luck
Feb 16, 2009 at 10:12 PM
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