Yesterday i had some free time so i thought "why not do an engine oil change" seems easy enough. warm up the engine, use a 17mm socket and drain the sump, retighten and fill the engine with new oil.
Simple untill i'm under the car undoing the sump plug and its loose spinning and spinning but not coming out. i guess someones rethreaded the hole after many oil changes. So with no luck getting the plug out i decide to do it up and maybe take it to a garage. Start doin it up and then 'Crack' the hex head of the bolt sheers right off and hits the floor. Oil pouring out 'into a bowl'
http://i82.photobucket.com/albums/j275/lov_train/Sumpplughex.jpg
After some thoughts of "i'm screwed and this is going to be a pain in the ass" i managed to look at the hole and finally relised the part that was left in the sump was hollowed thread.
http://i82.photobucket.com/albums/j275/lov_train/Hollowthread.jpg
So i managed to get it out without drilling it out.
So the question is why do BMW make the plugs hollow? it makes this thing more easier to happen cause it weakens the bolt. but then again if it does happen its easier to get out.
http://i82.photobucket.com/albums/j275/lov_train/sumpplug3piece.jpg
Anyone else had this happen to them or someone they know. i'm sure i'm not the only one.
I'm now off to buy a new sump plug which are luckly only about £2

:)

Common issue. Plug is drilled to allow it to break before the threads in the sump are stripped (sacrificial plug). It did its job.

and for this we are thankfull. RIP sump plug. died in the line of duty. 11/09/06

As an FYI, the drain plug is only supposed to the tightened to 18ft-lb, which is a lot less torque than you'd think. If you tighten the plug with a torque wrench there's pretty much no chance of this happening.