Well one thing you can do is put in a valve in the engine bay to shut off water supply. That will insure no heat in summer. Didn't know some of the heater stuck out like that. Thought they were all inside cab. If I am seeing that right, you are getting fumes/smells/heat inside cab from engine thru that open hole? AD folks will help further.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn