So, I recently noticed coolant puddles under my R34 coupe nothing major small puddles each night, after inspection I found that one of the core plugs is leaking. In itself this wouldn't be a major problem just knock it out and knock one it, however as can be seen in the attached pictures after removing most of the major things in the way I came across an issue. There is a fitting that is pressed into the thermostat housing that allows for coolant to flow to the heater core, this fitting is blocking me from removing the core plug, and before I go do something stupid like break it, does anybody know how to remove the heater return fitting in the thermostat housing, and no it doesn't just come out easily is quite tight and I don't want to but to much force on it in case I am doing something wrong that will break it.
Thanks for any help, pictures of fitting below