Thread:Estacaco/@comment-2A02:C7F:B82E:0:39C9:29DC:C35A:165A-20171230172651/@comment-70.76.123.196-20171231153726

Unfortunately that means the other end of the bolts are spinning in the old heater core box. When I had that problem I used vice grips to hold the end of the bolts in the engine bay then an open wrench to loosen the nuts.