coolant or exhaust

Is anyone familiar with a cast aluminum housing for an M-15 cooling system that is Universal part number 299943? I think this mixes a coolant system (antifreeze, etc.) with the raw seawater cooling. This riser (it really looks like a manifold to me) has cracked beyond what I think would be...

My cockpit locker gets pretty hot in the summer from the exhaust hose and hot water heater hoses as well as the expansion tank. I was thinking of insulating the hoses to keep the heat down as this heat tends to make its way over to the aft cabin too. Also the fridge compressor is in this locker...