causes of engine block cracking?

I have a 1998 5.7L penta Volvo inboard engine that I just took to a mechanic to service. He told me that the long block and manifolds are cracked because I didn't winterize it and it was full of water. I think that it is cooled by the water running through it that it sucks in when I have it in the water. It doesn't store water, so is it likely that I have a cracked block, or is it more likely that this guy is feeding me a line of bull?

 

If you didn't drain the river water and replace with anti freeze in the fall then ice most likely cracked your block. The river water, Raw water from here on, does in fact sit in the block and heads as well as the exhaust if you simply turn it off. Many in brackish water flush with a hose after each use to remove the salt water and keep it from lying in there and coroding the block.

 

He is probably correct. You have a raw water intake pump that draws water in thru the outdrive to a pump driven by the crank shaft. That pump will prevent water from draing out of the block even after you put on your trailer. Thats one reason you need to flush out the engine, especially after being in saltwater.

 

If it ran rough the first day of the season. TOAST.