Heating Help

Reply Subscribe

Thread Tools

Search this Thread

Jan 7, 2017 | 11:24 AM

jonmammenga

Thread Starter

Cross-Country

Joined: Aug 2014

Posts: 85

Likes: 0

From: Sioux Falls, SD

Heating Help

I just restored my 1979 F150 4x4. It is AC and I also replaced the heater core when I restored the truck. I remember the heater used to pretty much bake me out of the truck years ago and this winter it seems to not keep up very well. The supply and return lines to the heater core are both hot. Is there a blend door or something that is not functioning correctly or a vacuum operated solenoid not operating correctly? Any help is appreciated.

Jan 7, 2017 | 12:56 PM

78 PEB

Cargo Master

Joined: Oct 2010

Posts: 2,674

Likes: 16

From: Ideeho

New core.....I would bet that it is blend door related....or the way the heater core is sealed to the box.....the foam deteriorates over time......never owned a dent with AC so not much more help than that. When working correctly a dent heater will broil your toes LOL

Jan 7, 2017 | 01:20 PM

good to doo

Elder User

Joined: Feb 2014

Posts: 878

Likes: 3

From: british columbia, canada

On the back of the heater controls on the dash, there is a vacume unit with many vacume lines leading to it. These go bad.

Jan 7, 2017 | 08:13 PM

PapaBearYuma

Cargo Master

Joined: Nov 2011

Posts: 3,354

Likes: 48

From: Great American SouthWest

Perhaps the squirrel cage fan is not blowing. Do you have airflow?

Jan 7, 2017 | 10:39 PM

meangreen92

Logistics Pro

Joined: Jul 2005

Posts: 4,217

Likes: 154

Did you go with a colder thermostat in the engine?

Jan 8, 2017 | 11:18 AM

NumberDummy

Ford Parts Specialist

Joined: Nov 2006

Posts: 88,826

Likes: 783

From: Simi Valley, CA

Quote:

Originally Posted by good to doo

On the back of the A/C heater control panel on the dash, there is a vacuum unit with many vacuum lines leading to it. These go bad.

D5TZ-19B888-A .. A/C Vacuum Controlled Selector Valve Assy (Motorcraft YH-285) / Obsolete

CARPENTER NOS OBSOLETE PARTS in Concord NC has 292 = 800-476-9653.

1973/79 F100/350 & 1978/79 Bronco with factory installed integral A/C or Hi/Lo Comfort Vent System.

Factory installed integral A/C is combined with the heater. The A/C controls are in the same panel as the heater controls.

All the vacuum hoses used with the blend door motors and the heater water valve connect to this valve that also has the "kicker switch" mounted on it for the A/C compressor.

Jan 8, 2017 | 06:01 PM

burnthelight88

Laughing Gas

Joined: Mar 2015

Posts: 885

Likes: 2

From: Pittsburgh

As long as you have airflow it definitely sounds like you have a blend door issue. That being said, these aftermarket cores are usually cheaply made and sometimes bad out of the box.