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1967 mustang coupe v8 289
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Discussion Starter #1
This just started happening. a fair amount of antifreeze is leaking out the bottom of the car. in two places. the last pic looks like the previous owner already tried to seal it up with some kind of foam? the other spot where the majority of it is leaking looks like a hole or crack. does it flow through that area? what is that spot exactly and is that a big job to fix?
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That would be your heater core leaking up under the dash on the passenger side. Take a look. I doubt it's been leaking that long....you would have known it.
 

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1967 mustang coupe v8 289
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Discussion Starter #4
the heater core would leak that much that it's coming through the floor? yikes.
 

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67 coupe, 69 Sportsroof, 86 hatchback
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The "foam" is actually old sealant which appears to be no longer sealing. Lucky you because if it was it appears you would otherwise have a small swimming pool of green in the passenger floor. I expect it is soaking as it is.
You might like to remove that plug as is makes a convenient drain for cleaning up. You can buy a full set of new ones pretty cheap if the original is cruddy. Also you will want to use some kind of new seam sealer upon replacement. Like as seen in your picture but hopefully a bit neater.
 

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1967 mustang coupe v8 289
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Discussion Starter #6
The "foam" is actually old sealant which appears to be no longer sealing. Lucky you because if it was it appears you would otherwise have a small swimming pool of green in the passenger floor. I expect it is soaking as it is.
You might like to remove that plug as is makes a convenient drain for cleaning up. You can buy a full set of new ones pretty cheap if the original is cruddy. Also you will want to use some kind of new seam sealer upon replacement. Like as seen in your picture but hopefully a bit neater.
after double checking, the passenger floor does seem a little damp. but not too bad. what plug should i remove? that last picture is just a hole with a soft spongy material. kinda like a vent duct.
 

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Remove the front seats and front carpet section, you'll see two Phillips screws holding the oval plug in the floor pan. Remove and replace the heater core. Be sure your carpet is fully dry or replaced before you put it back or you'll have even more rust problems.
 

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1967 mustang coupe v8 289
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Discussion Starter #8
Remove the front seats and front carpet section, you'll see two Phillips screws holding the oval plug in the floor pan. Remove and replace the heater core. Be sure your carpet is fully dry or replaced before you put it back or you'll have even more rust problems.
the heater box looks to be leaking as well. would it be wise to replace both?
 

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1967 mustang coupe v8 289
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Discussion Starter #9
I just pulled up the carpet from the passenger side and found this. looks like previous owner just threw some cardboard under there. i dried up the puddles and i'll order a plug. looks like the leak is coming from that black rubber hose in the top of last pic. should that have clamps on it? should i replace that?
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So a PO cut a beer can open and used it to make a patch!! They actually make a plate that fits over that oval hole and is held in place with 2 screws.

I do not know what that rubber hose is. Can you take a photo farther away from it?
 

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Yep, heater core time....
 

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1967 mustang coupe v8 289
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Discussion Starter #12
So a PO cut a beer can open and used it to make a patch!! They actually make a plate that fits over that oval hole and is held in place with 2 screws.

I do not know what that rubber hose is. Can you take a photo farther away from it?
haha thats what it looks like! i tried to find a date on that box. its a flat peice of beer box with a flat layer of aluminum under that. looks like he cut an actual beer can and layed that under it as well. the black rubber hose is all the way up in the top left corner near the console
 

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1967 mustang coupe v8 289
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Discussion Starter #13
So a PO cut a beer can open and used it to make a patch!! They actually make a plate that fits over that oval hole and is held in place with 2 screws.

I do not know what that rubber hose is. Can you take a photo farther away from it?
more pics of that black hose:
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looks like the leak is spewing out from that hose
 

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The black hose is the air conditioner condensate drain and you should consider yourself lucky... the heater core looks like it's been leaking for a while and without the a/c hose your floor would have been the main repository for all that coolant. The heater box will need to come out as the heater core is located inside.
 

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Discussion Starter #15
The black hose is the air conditioner condensate drain and you should consider yourself lucky... the heater core looks like it's been leaking for a while and without the a/c hose your floor would have been the main repository for all that coolant. The heater box will need to come out as the heater core is located inside.
i removed my a/c condenser when i replaced the radiator recently. i didnt put it back since the a/c isn't working atm. i did remove a long hose from that general area from that box inside the engine bay to the condenser. could that be causing it to leak?
 

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the heater box looks to be leaking as well. would it be wise to replace both?
The heater box is leaking because the heater core is in it, and the core is leaking. No need to replace the heater box, just the core.
 

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Maybe the heater case / box will still be in good shape. You can get a heater core from a local parts house or from your Mustang parts vendor. I recommend rebuilding the case with an inexpensive Daniel Carpenter foam kit from the vendor. Here's a photo of the last one I reconditioned, before and after.
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It's also a good time to do a cooling system flush and fill, replace any and all hoses if needed. And the floor pan...welcome to the Domino Effect, also known as "project creep" with your VMF buddies !!
 
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1967 mustang coupe v8 289
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Discussion Starter #18
Maybe the heater case / box will still be in good shape. You can get a heater core from a local parts house or from your Mustang parts vendor. I recommend rebuilding the case with an inexpensive Daniel Carpenter foam kit from the vendor. Here's a photo of the last one I reconditioned, before and after. View attachment 749110 View attachment 749111
It's also a good time to do a cooling system flush and fill, replace any and all hoses if needed. And the floor pan...welcome to the Domino Effect, also known as "project creep" with your VMF buddies !!
i guess that will be my next quarantine project. i looked at a few guides. looks tough to do. but i have nothing but time now
 

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1967 Mustang Convertible
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Here is an article on changing the heater core. Its not hard, just kind of cumbersome working underneath the dash.


You can bypass the heater core in the meantime if you wanted to continue to drive your car around.
 
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Discussion Starter #20
Here is an article on changing the heater core. Its not hard, just kind of cumbersome working underneath the dash.


You can bypass the heater core in the meantime if you wanted to continue to drive your car around.
mine is a 67. how do you bypass it?
 
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