Vannin' Home Forums Ford Troubleshooting Heater Core Box Help 1983 GMC Vandura 2500

Hey Van Dudes I'm back with another problem I need some help with.
My heater core is shot, and for the past 3 weeks, I've been trying to fix it! I just want to continue my adventure.

Recently I figured I could bypass the heater core for the summer, and fix it in the winter. The only problem is. that after bypassing, coolant is still leaking out by the passenger's footwell! I'm fairly confident that it's just leftover antifreeze pooling in the big plastic box. So my question is this:

How to i get all that antifreeze out of the box without having to take apart the dashboard?
PS I've already flushed the heater core with water multiple times.
My ideas right now are; drill a hole in the right place; drive around town get things sloshing about, or cut a hole in the box.

PHOTOS: https://imgur.com/02TXRIt https://imgur.com/YnNIPYG

hook up a shop vac to one of the lines that you cut N suk it out.

Don't drill a hole in the heater box. Just blow some compressed air thru the hoses or vacuum it out like stated above.

I will try that... but there doesnt seem to be any coolant left in the heater core... its in the box....

Can you remove the insert to the glove box to access the area?

alright, I didn't listen to any of you and I drilled some holes. Antifreeze poured out probably around 2-3 cups worth. after it slowed down I sprayed water in there and flushed the rest out. nice and clean, just gotta silicone the holes up
Pic https://imgur.com/GYfVuDS