Cracked Block Probability
 

Hi, reading your post years later lol.

I have cracked a block by pouring cold water into a non running engine while it was hot (not just normal operating temperature)

I had refilled this engine hot multiple times before, while running, no problem..... This time I shut it off, waited for the pressure to go down to where I could remove the cap sort of safely, then pored water in,
- this time without starting.

I poured about half a gallon in, and I heard a loud pop. The engine block was cracked and the coolant ran into the cylinder. 3/10 would not do again.

I think the danger is higher with a cast iron block, but I'm not sure.