Finished up another Tech Counselor to-do from my 12 October visit. by tightening the oil cooler bolts after adding thread lock to them. Torqued several nuts on the belly of the fuselage. Painted torque lock onto the nuts as well as on to all 12 wing spar nuts. Tried a preliminary fit on the cabin heater muff (to attached to the muffler), but came away completely stumped on how to fit it. I'll call Zenith to see what I need to do to make it work.