75 v6 coolant question

A few weeks ago, my V6 developed the "rattle of death" (butterfly valves sticking). It just appeared on day on start-up, no gradual noise build-up.

2 days ago, the temp gauge shot to the top and the fan kicked-in. Filled with water and it got me home. After cooling down, if re-filled (the volume of coolant indicated that a substantial leakage had occurred)

When starting the car again, the rattle of death has gone. Back to its old smooth purring engine.

My question: Is there some correlation between the rattle and coolant levels?

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