Heater only blows luke warm air

Tiny
VERYCOLD
  • MEMBER
  • 1994 FORD F-250

Greetings, owner complained of no heat. Thermostat was replaced as was heater core. Both lines to the core feel hot. The blend door next to the heater core appears to be functioning properly. I s there another control in the duct system to direct more air into the heater core? Thanks
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Friday, January 29th, 2010 AT 7:19 AM

24 Replies

Tiny
MERLIN2021
  • EXPERT
There is a tech bulletin on this, It is attached below
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Friday, January 29th, 2010 AT 7:57 AM
Tiny
VERYCOLD
  • MEMBER
Thanks for the info on the blend door cable. I removed the 7 screw cover for access to the heater core. After moving it both with the cable and without it did not appear to close completely. I used a hook shaped screwdriver and was able to reach in and rake the bottom of the plenum next to the door. I heard a rattle and was then able to squeeze my hand in and discover an ink pen apparently had fallen through the defrost and blocked the door from complete closure. After removing the pen and reassembling the door the heater now functions properly and blows 125 degree air.
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Friday, January 29th, 2010 AT 12:21 PM
Tiny
MERLIN2021
  • EXPERT
Nothin like stayin' warm!
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Friday, January 29th, 2010 AT 1:05 PM
Tiny
CGARTEN333
  • MEMBER
  • 1994 FORD F-250
  • 130,000 MILES
My heater in my F250 blows cold air. I was going to replace the heater core but when I take the screws out of the plenum I can feel hot air coming out the bottom, so I don't think it's the heater core. My assumption is I have an actuator not functioning properly. Any ideas how I can check this.
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Are both heater core hoses getting hot?
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
CGARTEN333
  • MEMBER
Yes
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
STEVEN-RAMOS
  • MEMBER
  • 1997 FORD F-250
  • V8
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
Does the f-250 have a heater control valve?
What should I check for to get heat?
Thank you.
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
BLACKOP555
  • EXPERT
I cant say for sure if yours has one or not, but the first thing you should do is warm the vehicle up to normal temperature, then feel the heater core hoses directly at the fire wall.

Is one of the hoses hot?
Neither hot?
Both just warm and not as hot as the upper?
Both hot?

Post back.
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
GARY ALLISON
  • MEMBER
Mine has one hose hot going to heat thru the firewall Gary allison
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
GHRABIK@COX.NET
  • MEMBER
  • 1997 FORD F-250
  • V8
  • 4WD
  • AUTOMATIC
  • 155,000 MILES
I have a 97 Ford F-250. The heat only works occasionally, usally at an idol and sometimes while moving. Tried to flush heater core out. Could this be a bad heater core, or maybe the heater control switch?
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
RASMATAZ
  • MEMBER
Check the thermostat, coolant level, heater core if its clogged, heater control valve and air blend door/actuator-
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 1994 FORD F-250
  • 130,000 MILES
My heater doesn't seem to get hot. The AC works fine, but when I switch to heat it doesn't warm up. The temp gauge works, the hoses to the heater core are both warm. I took the cover off the heater core and there is hot air coming out the bottom of the cover. It doesn't seem to blow much air when I switch to defroster either. Any ideas? No matter where I set the knob (floor, vent, or defroster) I don't get hot air. I checked the knob for the heat control and it seems to be working properly.
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Is the blend door motor moving the way it should to allow heat into the truck?

Roy
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
AKTYREMAN
  • MEMBER
  • 1997 FORD F-250
  • V8
  • 4WD
  • MANUAL
  • 120,000 MILES
I have tried everything, new heater core, tore apart the dash and all valves are working ok(heating and cooling vents) great air flow, when you reach up in the box it is very warm. You get more heat when its on vent than when on heater. Any ideas?

Thanks
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
RASMATAZ
  • MEMBER
Did you replace the thermostat and also check for a heater control valve that's malfunctioning
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
AKTYREMAN
  • MEMBER
Yep I did, can't find any valves that are malfunctioning, they all seem to open and close right.

Thanks
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
RASMATAZ
  • MEMBER
Is there a valve attached to the heater hose before it enters the heater core
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
AKTYREMAN
  • MEMBER
Nope just straight in, its hot going in and out of the heater core
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
MTWS 525
  • MEMBER
Did anybody figure this one out? I am having the exact same problem with a 97 F 250. Thanks in advance.
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Monday, December 31st, 2018 AT 9:24 AM (Merged)
Tiny
JBSILVA2123
  • MEMBER
  • 1997 FORD F-250FORD F-250
I have a 94 Ford F250 regular cab 2wd. It has the 460 engine and a 5spd. The a/c and heater are not working. I can turn them on but there is no cooling and there is not heating. I am not that concerned with the ac, however I would like to heater to work. Someone advised me that it may need a new heater core. Is this something difficult to change or repair?
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Monday, December 31st, 2018 AT 9:24 AM (Merged)

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