X5 blowing out smoke????

[BimmerDude]

Hello again everybody. I was driving from work tonight and I noticed when accelerating I saw smoke coming from the back end of the X5. I quickly pulled over into a parking lot. I was hearing a sound also coming from the engine. I quickly popped the hood and saw a little smoke but nothing big. I looked under the car to see if there was any fluid, but nothing. Called a tow truck (3hr wait). Once he came I saw engine oil on the ground. Not a lot but enough that it looked like coolant had leaked all out. Can someone tell me what this may be? I'm think head gaskets or valve cover problem? Or maybe worse. Need info on this asap. The car is at BMW right now waiting for them to open at 7am. Thanks.....