Volvo Penta 5.7 possible freeze plug out

[moffat]

I have a 2004 Reinell 204 with a Volvo penta 5.7 with a carb. The last owner put a 5.7 in last year and before it had a 5.0 so I am unsure of the model. I am not sure if the block is a volvo penta or if he used another block but he used the 5.0 manifolds, carbs,exhaust,etc. I put the pink antifreeze in it last fall but we had 2 nights of -42 degree weather plus the wind factor with the warmest temp being -10 degrees during the day. The motor starts and rund good with no water in the oil and the engine does not over heat but it pumps the water into the hull instead out of the boat. There is not a lot of room to look to see where the water is coming from but using mirrors the water is running out from the back of the motor by where the starter mounts.
I do not know if the freeze plug (expansion plug) or plugs are out because they are not visible in the rear of the boat. I am planning on pulling the motor to see if it is the freeze plugs unless someone knows of any hoses or something that I should check before pulling the motor. Is there anything that might fit this discription that I should check before pulling the motor?

[Scott Danforth]

they are core plugs (used to get the foundry sand out of the core for the casting process), not freeze plugs. hopefully its something simple and not a crack.