water in the cylinders.

[joinrdie]

When water gets in there, your car will start running generally crappy, and will blow steam out of the tailpipe as the water boils off, plus, the coolant will be consistently low because of this boiling.

You should be fine just by replacing the head gaskets, flushing the coolant and changing the oil. When the water gets in there, you get some water in your oil, just like the oil that gets in your water passages. This is what damages bearings and oil pumps and stuff. Generally, you'll notice the steam and the oil in the coolant before you have to worry about seizing the engine, just make sure not to drive it if that happens in the future.