Hello all! I have had a good season with the boat and took it for one last ride during the week. On the way back from the restaurant the port engine overheated. Upon returning and inspecting I found both plastic manifold elbow/drains had blown out. I scraped out the remaining plastic threads and installed new elbows. I noticed when I went to fill the cooling system the cap was loose and the brass housing was bent. A lot of pressure built up for sure. The filler cap housing is round on one side for the hose, then the cap in the center, then a flat square surface with four bolts. I need to know where to source this part! Also, how much coolant should the boat take, and yes I need to find out why it over heated, and it does it really fast when it does.. maybe head gasket, maybe a stuck thermostat..that engine had been getting harder to start possibly unrelated. what causes those elbows to both blow out of the manifolds, they probably melted from the heat first. Thanks1