I need to know what this thing is called. I’ve always called it a water crossover, but that’s not it. Mine is real corroded and I don’t want rusted metal chunks floating around. It’s the part next to the old flywheel. Bolts on top of the intake manifold. Thermostat is inside it and sits in the open hole on the front of the manifold.

thermostat housing........cross over sits in place of the water pump

thank you!

https://www.mercruiserparts.com/1641...-part-bul-99-2