over heated and coolant everywhere

[srmmmm]

Hopefully all you did was blow the expansion tank. You'll definitely need a cooling system pressure test to check for blown head gasket though.

2002 X5 3.0 244,000 miles
2004 325i 109,000 miles

[mgmarsh39]

That belt must have stretched a crap ton since the last time I had an oil change. The techs said everything was fine not a month ago.

[J.Belknap]

Originally Posted by srmmmm

cooling system pressure test

Yes. This would be the first thing to do before disassembly. Pour some distilled water into the system and locate the leak via a pressure test.

Edit: The order of failure suggests the belt sliced through a hose on its way off the drive. What caused the belt to come off the drive? Inspect your tensioner, etc.