Crystals in exhaust

[Han]

Hi All,

Looking for some advice. We recently removed the exhaust riser on our engine and discovered these crystals in the exhaust outlet on the block.

There is only one thing I can think of that it might be. Last summer our exhaust high-rise snapped due to a faulty weld and with no pressure to push it out some cooling water backed up into this area. I thought we would have noticed this at that time if it was there then, but maybe we overlooked it? Any other ideas what could cause this?

The engine runs fine, no smoke or anything. Any input appreciated.