heater leaking coolant inside cab...

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I took off my heater unit when I was getting at my wiring harness to make fixes and have room to see, and now that I have reinstalled it I have coolant that wants to drain out the bottom. My pipes are attached well with clips so its not coming from those, its somehow coming out a different spot and draining out the bottom. Anyone have any ideas on how i can get at that or where it could even drain from? Im trying to locate where its coming from but I cant seem to figure that out.
 
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Here are some pics - I do not have the duct attached yet or the defrost tubes because fitting it back in has proven to be very difficult, but the main issue is the leaking out the bottom & i need to figure that out. Maybe I overfilled? I don’t know if that would even cause that but just throwing that out there.

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Skreddy

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Inlet/outlet won’t matter because it’ll keep leaking unless you drain the coolant below the level of the heater core or either hose going to it.

Are you sure you don’t need to tighten one of the hose clamps to the core? I’ve had that issue where I think they are tight, but coolant will weep out and run down along the core, collect and drip out the bottom of the heater box. Either that or there’s a crack/hole/etc in the core itself and it’s leaking, coolant following same path out. In that event, it needs to come out for fix/replacement (cityracer has them new).
 
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Yep leaking heater core, remove and inspect. A local radiator shop might be able to fix or find a good one in the classifieds.
While it's out you can pressure test it to be sure.

I'd bypass it in the engine bay for now
 
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Another possibility that’s easy to check is the hose connections just inside the engine bay side of the firewall can leak and the coolant weeps right through firewall grommet and into the passenger compartment. And if you have original copper pipes with the insulation the coolant can run between the pipe and the insulation and will leak out wherever there’s a hole in the insulation.
 

middlecalf

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^x2. It might work, don’t have history with that particular product, but do with other stuff and it’s amazing how it finds its way into channels and passageways that aren’t meant to be sealed off.
 
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Ok i guess ill remove and inspect.

i do have one clarifying question though - *if i attached hoses correctly and clamped correctly and still get leak ... does that mean it must be leak in core? or is there any other way it could leak? im not seeing any other reason but i want to clarify that
 
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Well I guess anything is possible. If the copper lines/fittings are corroded there could be a bad connection with the hose no matter how tight you have the clamps.
Letting it drip and run down to the bottom.

Without the stuff in the engine bay mentioned above there's 3 options:
- inlet leaking
-outlet leaking
-core leaking
 

GA Architect

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Well I guess anything is possible. If the copper lines/fittings are corroded there could be a bad connection with the hose no matter how tight you have the clamps.
Letting it drip and run down to the bottom.

Without the stuff in the engine bay mentioned above there's 3 options:
- inlet leaking
-outlet leaking
-core leaking
I had some minor pitting on my brass connectors, so I used this to help seal the joints:

1645056223698.png


I do have a set of clean brass connectors, so one day I'll replace the pitted ones.....maybe one day.
 

TheHardWay

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FWIW, one of the wire clamps on mine leaked, no matter how much I tightened it. When I removed it I found it was slightly out of round. Manipulated it back to round, reinstalled and that fixed the leak.
 

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