So I let my truck sit for a little over the winter and hopped in it to drive the other day and noticed that it was leaking anti-freeze. I pin pointed the drip to this area and I think it is coming from the box in red. Sorry about the size of the image it has to be under 2mb.

Does anyone know what the box is and if it would be the cause of my leaking anti-freeze?

1985 ford f-150. 5. efi

enter image description here

  • Cover over the heater core.
    – George
    Commented Jan 9, 2021 at 2:44
  • Thanks @George! do you know if that would make sense to have anti freeze there?
    – Sam Orozco
    Commented Jan 9, 2021 at 2:44
  • @George I like it and it looks like it makes sense. Thank you
    – Sam Orozco
    Commented Jan 9, 2021 at 2:50

1 Answer 1


The heater matrix (heater core) for the cabin heater is in that box.

It is likely that the matrix (core) is corroded and will need replacing. It looks like it should be fairly easy to access it, unlike on some vehicles where you have to totally remove the dashboard.

First thing to check is that the leak isn’t just from one of the two pipes that can be seen connecting to the matrix (core). If it is leaking from the pipes, you may be able to disconnect them, clean any corrosion and refit them.

  • 1
    For the OP: The term "heater matrix" can also be called a "heater core". Depending on where you are at in the world will dictate what someone else may call it. Commented Jan 9, 2021 at 17:28

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