Trouble Shooting a bypassed heater core

[mattman079]

Hello,

Hopefully someone has gone through this problem or has some helpful information. I bought my 83 Spider and noticed the heater core was bypassed entirely (Tubes never run to holes in firewall, but just connect to each other).

I would love to drive this fall and was curious if anyone has any tips on how to test the heater core without draining the coolant and hooking the tubes up correctly? I'm assuming the previous owner found out it was leaking and decided to just bypass it rather than fix it, but want to find out without pulling my entire console out or draining all the coolant and testing for a leak the normal way.

Thanks for the help in advance!