300 SD I respect your experience but do'nt you think the noise is a little high pitched to sound like a bottom end noise? I think if you look back at a posting fireman 1073 made he posted a vidio that sounded just like my noise and I thought he also posted 2 pictures of a prechamber that after pulling and inspecting it saw a small hole in the bottom of it and that was rattleing around in there causeing his noise unless I understood him wrong. Do the prechambers have any holes in the bottom just the sides correct? Was just wondering before I throw in the towel and yank the motor if maybe I should pull a couple prechambers and examine. I did have about 2 glow plugs that a bit of the tips were burned or broken off but they still worked.