I think the heater core on my 73 F100 custom 302 has sprung a leak. The box under the dash started making a hissing noise and I noticed it was wet. On the passenger side I noticed a pretty constant drip happening which is a green antifreeze color and was warm to the touch.

Is this a dreaded heater core leak I've read about?

What advice would you give? Should I drain it, run radiator stop leak stuff, re-route the hoses and cut out the heater? Bite the bullet and replace it? This is Texas so I won't be needing the heater anytime soon and at most maybe 1 week out of the year.

I found a thread I think for an F150 that said the part was like $50 but it's a PITA to remove, took him like 10 hours or something. I read that you have to remove the dash; is that referring to the actual metal frame part?

Shiz shiz shiz!

 

ARE you an ac truck? If ac it should be about 2-3 hours if you follow the instructions, if non ac then like 1 hour should cover it. I have done enough of them and an ac truck needs evacuated to make life easier, but if dealer installed ac, then it will be a rodeo! I would say you need a new heater core.

 

Do not use stop leak. Bad stuff IMO on everything else. Just disconnect the hoses from the heater core ends sticking out the fire wall (for now) and connect them together with a metal splice tube and then replace the heater core when you can.

A/C truck sort of a PITA, none A/C couple of hrs. No need to remove the dash either way.

 

Yes it's an AC truck. I don't want to use any stop leak, eggs, or spices cause those are fixes that will eventually fail. I see the part is cheap but have read with AC it's a PITA. I've attached a photo from where I think the leak originates.

You've put me somewhat at ease telling me I don't have to remove the dash. Phew!

I also noticed the lever attached to a cable doesn't move like the lever for Off/Floor/Defrost.

I found a thread that said you could loop some lines to cut the heater out of it. Again, in Texas I won't ever hardly have to use it.

I looped the 2 lines pictured but still get a drip in the cab.

There's 2 lines going into the cab in the red circle; one runs to the AC (blue line)and the other (red line) to the radiator. Do I need to plug the radiator one or loop the 2?

Am I able to cut out the heater core and still have AC?

Also, I notice on the 2 ports i cut out that one is wet and one is dry; could there just be a blockage in the heater core preventing the flow of coolant?

I appreciate any insight provided.

 

Looking at your underhood pic where you overlaid all the red and blue lines...

I see a York/Tecumseh 2 cylinder reciprocating A/C compressor, with the suction line marked with Blue, and the high-side line, marked in Red, which goes up in front of the radiator to the condenser. Those ain't coolant lines! They also shouldn't have radiator hose clamps on them!

As far as a disconnected heater core continuing to drip coolant, it will until the level in it drops enough to not reach an outlet. Could blow some air into one core tube to blow the coolant in the core out of the other tube.

 

Ok, good to know. Wanted to make sure I had covered all points of coolant to the cab. Guess that means the AC is independent of the heater so I should be able to run the AC once charged?

I'll get some tubing on there and see if I can blow out any fluid from the core. Still leery about trusting the unit though. That can be a project for fall, if we get that season this year.

Any one recommend a source for removing the heater core specific to the F100? Searching the site through good always pulls stuff for F150, 250, 350, excursions and others. I saw the process on the F150 so I'm thinking it's similar but want to double check.

 

Looking at the underhood pic (does not have the huge evaporator case on the right side), your truck does not have factory A/C, it has dealer installed A/C

Two types of dealer A/C:

1) Deluxe dealer installed A/C is combined with the heater. The two A/C switches are located in the HUGE bezel that sweeps across the entire right side of the dash, covering up the glove box.

There's a hang-on glove box that bolts to the bottom of the dash.

2) Economy dealer installed A/C is not combined with the heater. The two A/C switches are located in a panel that also contains two registers. This panel fits into the dash to the left of the glove box.

Economy A/C uses the same heater core as 1973/79 F100/350 & 1978/79 Bronco with heater only.

 

I've attached some photos; does this help indicate whether it's deluxe or economy?

The area behind the glove box is pretty empty so economy?

 

A/C panel to the left of the glove box: Economy dealer installed A/C

 

No big box in the engine compartment NO factory a/c. Looks like you have dealer installed a/c.

Correct in where you disconnected the heater core lines, and yes put some compressed air in one side to get the left over antifreeze out of the heater core.

No need to disconnect the red or blue. FYI red and blue are under pressure and are a/c lines only.

I do not know if you take the heater core out of the equation if you can still run a/c.

A/C info sort of... but it is factory installed a/c info. 1979 F100 Air Conditioning

FTE member in the same boat with you. https://www.ford-trucks.com/forums/1...ater-core.html

 

I just did a heater core on my 78 that has the same setup(dealer installed economy a/c). The only way to get that heater box out is to take out all bolts/screws that hold the dash, and move it back just enough to drop the heater box out. One of the most difficult parts was getting at the top screws that hold the air vent housing to the heater box.(had to break one). There is a metal bracket that holds the a/c blower housing to the cowl. Make sure to remove the screw that holds it. With the glove box out it should be fairly easy to get to. The a/c box should move back with the dash assy. This a/c will work on its own without the heater. Looking at the pics, yours is missing the temp control. They are available from nostalgicac.com for around 20 bucks.

 

Can you clarify this temp control or share a picture?

 

https://nostalgicac.com/complete-ac-...ord-truck.html

I do know this for sure, when you remove the glove box, tape the pressed in edges, they can be very sharp.

 

Sorry, my brain might be farting but are you referring to the control where you set temperature, duct position, and fan strength? I have what's on the truck and on the nostalgicac website all I'm finding are the similar.

Noted on the box edges. Unfortunately the PO told me he took it in for service and they took the glove box liner out and never put it back in. I'm looking into fabricating something but need to find some dimensions.

 

Cardboard glove box. 1973-1979 Ford Bronco and F Series Truck Glove Box, Replacement-Broncograveyard.com

Plastic 73-79 Bronco & F-Series Glove Box, Ultimate Plastic Liner-Broncograveyard.com