Hi Blaine, a D-179 at 3200 Hrs has hardly been broken in yet. My brother has one in 454 with well over 15,000 Hrs still starting and running great. No oil consumption. As others have said slobbering in cold weather.
A couple little things that may help:
1) A cover over the front of rad to bring temp up.
2) The only difference between 454 and 464 is the fuel screw is turned out on the injection pump to give 464, 45 HP vs 454 40 HP. So when the tractor is idling around in the cold weather you can lean the fuel mixture down a bit by not pulling the STOP/START/RUN lever all the way to the top. Try leaving it down a 1/4 inch or so. If you require the full power then pull it all the way up to RUN.
Hope this helps