Yesterday I detailed the outside of the Stealth. I parked it and went inside. Today I went out to pull it back in to do the inside when I noticed that the coolant level light was on. It has never been on before. I turn off the car and check the overflow and it was empty. The system was sealed, I've never seen any leaks, and where the car was parked there was no evidence that it had released the overflow on the ground.

I can only think that for some reason after I got home and parked the car to wash it the coolant released onto the ground from the overflow and not noticing it I started washing it and I would have never known. I also checked the oil and I can't see any white grease so I don't think oil is getting in the crackcase and I don't think a head gasket has gone. I've never seen steam from anywhere. I am getting a white smoke from the exhaust since using Sea Foam but it doesn't smell like coolant.

So, any ideas of what happened to the coolant? Slow burn off or sudden release? Also, what would cause either besides a cracked block or head, busted head gasket, or loss of pressure in the system?