Smoke From Behind Dash

[homedog56]

Hey guys last night after having a bit of a spirited drive i pulled over and turned the car off all of a sudden my passenger and i noticed smoke coming from where the stereo sits behind the dash (Head Unit is currently out). Now i have bypassed the heater core because it had rusted out and it did smell a little like coolant but i dont understand how it could be heating up, is there anything else it could be? Is it just the two hoses that run in and out of the heater core?

It appears that at one stage my car might have had an aftermarket temp gauge because the top hose is cut in half and has an orange insert there with what looks like a copper wire running thru the firewall should i need to block this off aswell?

Any help would be greatly appreciated!

Cheers