Try wiggling the spindle that turns the water-pump mechanism. If it wiggles/woggles at the spindle as to indicate an out-of-balance rotation, then it likely indicates a faulty water-pump.

If you don't plan on replacing the water-pump yourself; then you can re-fill the radiator and overflow res, and quickly limp the VX (while the engine is still cold from sitting overnight) to a nearby mechanic/shop for repair.