What does a snapping head bolt sound like?

[ike84]

Took the boat out for her maiden voyage of the season today - 1990 sea ray 220 cabin cruiser with 7.4l mercruiser (454 big block Chevy rigged for marine use) and bravo one outdrive. Warning buzzer went off as soon as she fired up - low on gear oil. Topped that off and started right up no problem. Didn't make it out of the harbor before the warning buzzer went off and the temp needle pegged. Immediately shut it down and opened the engine compartment to copious black smoke blowing around the valve covers and 4 or 5 distinct metallic ping noises. After letting it cool off a bit she started back up and we limped back to the ramp and got her on the trailer. Again. More black smoke and a few more pinging noises after shutdown.

I think what happened is that the water pump failed, the block overheated, the heads warped, and the head studs popped. That's the only way I can explain the ping noises, unless that was the sound of the block cracking multiple times but I doubt it.

I was going to pull the water pump and then go from there. Not sure about flushing the cooling system - I will need to read about that. Will start get up again sorry that to assess further damage but I suspect that it won't be pretty.

RIP Blind Squirrel, we loved you dearly.

Btw, does anyone want to buy a boat? She needs a new motor but otherwise she's in fantastic shape!

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