I parked my blazer on the street. When I came back, I noticed leaking coolant below it. The resivoir was dry. Anyway I drove back to the hotel (1 minute drive) and left it overnight. In the morning, I poured water in and started it to find the leak, but nothing! I drove around till it was at full temperature, and it performed normally with the water. Any idea what this phenomenon could've been? Thanks.

 

Year, make, model, & engine? If 96 or newer, probably leaky lower intake manifold gaskets, very common problem.

 

It should be in my sig, if not its a 98 blazer zr2 4.3L

So that would cause it to either drain completely or hold 100%? I find it weird for it to go full-dry so suddenly then hold water without any drips at all right after.

 

was the radiator empty as well, or just the bottle?

 

I didn't check the rad, but it must've at least been low because the engine was operating slightly hotter than it usually does.