But also that can be a blown head gasket. If it has been really humid the last few mornings when that happens then that would explain the condensation comment above. But you might want to check and see if you can smell any antifreeze in the engine bay or if you have any leaks around the heads.
i know this is an old thread but i still get this. does anyone have this problem after the rain or whenever the car gets wet? i only seam to get this when the car is wet. I'm pretty sure it is condensation but geeze, every time it rains?