I searched for bad tim mx3 on google and came up here...between my HK3, swiftech xt, supreme HF, I have mounted my blocks at least 50X and never had a really horrible mount. then had 4 in a row with a new tube of mx3 (~bought 2 months ago). All my blocks/mounts were between 68 and 72C avg core temps...now getting 74 to 77 avg core temps with 2 new tubes of mx3.
Since I had just taken my loop down to change reservoir, I spent 2 hrs thinking it was air, etc, till I wised up and checked water temp...then looked at mx3 mount. First mount had 3 clumps of tim covering about 20% IHS, and watery crap running out sides...never seen anything like it...should have taken pics. mounted it 3 more times, same screwy tim pattern each time along with terrible temps, and different core temp pattern.
Found a very old 95% gone tube of mx3, and had just enough for 1 mount, and temps went back down to normal 68.5C.
Saw this thread about an hour ago, read post about possible separation not a bad thought,...so I took about 90% rest of that tube and squirted it out, and mixed it up, but same high temps and watery/screwy non-coverage of IHS, even trying second mount with 9mm pea size...still end up with almost no tim on block...just watery/clumpy mess.
Well, 5 hours to apply tim, must be a new record in stubbornness or stupidity...I was just starting to like mx3 after consistently getting about .5C better temps then mx2....but done with it now.