I'm going to stick my neck out, I think running wmo/tranny fluid/gear oil (i.e. a mixture of whatever it is that got drained out at the farm, sans coolant) might have caused the o-ring in my manifold heater fuel nozzle to fail. I started getting a healthy dose of oil right onto the top of the turbo. I could visually observe the nozzle leaking from the rear-facing end during operation. I pulled the nozzle, and found an intact o-ring, with flattened strips on the inside and outside of the ring. (Sides still looked pretty good.) I'm not going to fully blame my fuel mixture (which did include 20% gasoline) on the part failure, but it would be a good opportunity to advise on adding an appropriate o-ring to the goody bag of emergency parts, it looks like maybe a size 014 o-ring. --Someone please correct me on the size if I'm wrong-- I swung by Checker-Oreilly and asked for fuel resistant o-ring, got a close visual match (but no cigar), researched the rubber type--Buna-n, decided not to install it due to low oil resistance characteristics of that rubber. I am looking to go with a Viton or Kalrez type O-ring to replace it, as they are rated well for oil/chemical resistance. If the o-ring that failed in my duece was made by lowest bidder, it could well have been made out of Buna-n rubber.
Truck engine is still running great on multi-fuel mix.