Here's what is see from the pics. TB42 motor. The aluminum piece you took off is the thermostat housing and is missing the thermostat. That must be in there to allow proper water flow to the LP regulator. The exhaust manifold is no way connected to that thermostat housing. I think if you check the hoses for blockage and fix the kinks and put a thermostat in it, that should fix it.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.