Blown Engine?

I bought a used 1998 saturn sl2 about a month ago and noticed the coolant was very low last week. I refilled it on saturday. Today driving to work I noticed the temperature was pegged, then I went to pull over and heard a bang from the engine area, and smoke billowed out.
Oil is everywhere on the engine and 1/2 quart on the street where I parked. Sound like cracked engine block?
I had it towed to a nearby gas station to check it out. I guess I should have been checking that coolant every day.
Any thoughts on what the necessary repairs are going to be? Or why I was loosing coolant without any puddles? :disappoin
Never thought I'd be someone to blow an engine, never.

well it sounds like either headgasket went, or you had multiple problems. a rod could have blown through the side of the cylinder if oil was low. your just going to have to look around. does it look like oil came out of the intake, and coolant overflowed out of the bottle?

its hard to say what happened, but with a bang, id almost say the rod blew through the cylinder because piston seized in cylinder due to low oil pressure or low oil.

Yeah, the "bang" certainly suggests a thrown rod.