No, I haven’t. I am not familiar with the bubble test.
Local mechanic did one, and said it didn’t lose pressure, but the coolant is going SOMEWHERE. There are no puddles on the ground, doesn’t come from anywhere while idling, oil isn’t grossly contaminated...
I can’t be 100% sure about the specific spots, but as I said, no puddles. Before the Blue Devil I would full up with 12 gallons of unleaded and 1 gallon of coolant, so it wouldn’t be a small leak, I figure.