My MPV keeps losing antifreeze so fast that I have to refill it almost every 200 miles. There are no leaks on the radiator or hoses and no antifreeze drips on where I parked it. I'm sure it doesn't leak into the combustion chamber because it's just normal smoke coming out of the exhaust, without that tell-tale sweet smell of antifreeze. If it leaks into the engine oil compartment the oil would turn into a chocolate kind of color, but there's nothing of that kind.
The strange thing is, each time I refill the reservoir up to the "full" level and drive say for 50 miles, and then stop, turn off ignition and check the reservoir, the level would have RISEN half inch above the "full" level. But after leaving it overnight the level would drop half-inch BELOW the "full" level. If unfilled it would go down lower each day. What could be possibly wrong?

 

You may have a small leak in your coolant overflow tank. See http://forum.mpvclub.com/viewtopic.php?t=23200