My service department said they found an 8mm bolt with the hexagon head sheared into a dome, it is about 60mm long. Anyone have any ideas what its from? They think it might be timing chain rail? What about the oil pump bolts backing out? I can't see how the head would get worn if it is the oil pump bolot however....
Suggestions?

My service department said they found an 8mm bolt with the hexagon head sheared into a dome, it is about 60mm long. Anyone have any ideas what its from? They think it might be timing chain rail? What about the oil pump bolts backing out? I can't see how the head would get worn if it is the oil pump bolot however....
Suggestions?

The oil pumnp mount bolt backs out and hits the oil pump drive chain, so this could be the cause of the wear you see on it. Get them to drop the entire oil pan and check the oil pump mounting bolts, I bet they'll find at least one of them missing and the others could be loose.

good luck,

Oil pump bolt pictures.

http://memimage.cardomain.com/member_images/12/web/240000-240999/240317_65_full.jpg

http://memimage.cardomain.com/member_images/12/web/240000-240999/240317_64_full.jpg

http://memimage.cardomain.com/member_images/12/web/240000-240999/240317_66_full.jpg

http://memimage.cardomain.com/member_images/12/web/240000-240999/240317_67_full.jpg

(Pictures from "740iL'n" linked at www.e38.org)

Thanks guys! It was from the pump, stoopid mechanics didn't listen to me last service when I told them to check it!

http://www.terrysaytherauto.com/M60OilPumpBoltProb.htm