1997 Ford F-250 heat

Tiny
COUNTRYBOY3490
  • MEMBER
  • 1997 FORD F-250
  • 5.8L
  • V8
  • 4WD
  • MANUAL
  • 130,000 MILES
Yes my heater isnt blowing hot air like it should. I have flushed the heater core twice and changed the thermostat. When the defrost is on it blows lukewarm air. When I switch it to vent the air is hot then switches to warm air. And will switch to defrost on its own. When I switch the heat sources there is a bit of a delay. I was wondering what is causing this. Is the heater in the dash clogged with something or is there a bad relay somewhere?
Thursday, January 23rd, 2014 AT 5:05 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Are both heater core hoses getting hot? Have you checked for vacuum leaks in the vent door system? Have you checked the blend air door for operation?
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Thursday, January 23rd, 2014 AT 5:38 AM
Tiny
COUNTRYBOY3490
  • MEMBER
  • 2 POSTS
Yes both heater core hoses are getting hotlike they should. The temperature control door
seem to be working fine. No vacuum leaks that I know of. Although my truck leaks a little antifreeze from somewhere. And its only a few drops here and there.
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Thursday, January 23rd, 2014 AT 6:29 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If both heater core hoses are hot, then you have to have a problem with the blend air door. The idea that blower direction changes from the defroster to vent by itself leads me to believe there is a vacuum leak.
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Thursday, January 23rd, 2014 AT 8:47 AM

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