I have regularly used bio blends from 5% up to 15% year round in the upper midwest for several years. I regularly run thru Nebraska, Iowa, Illinois, Minnesota, Wisconsin, Indiana and bio is the name of the game are virtually all truck stops nowadays. I do have occasion fuel filter issues in the winter, since the fuel filter specs for my engine are about 7 micron. Gelling is not really an issue, but the denser bio will fill the filter media a little sooner in extreme cold. I have a glass bowl to see how much of the filter has been used, once fuel reaches the top, time to change. I go thru about 21,000 gallons of biodiesel a year and it works fine.
I only have some issues when ambient temps get into the the serious sub zero range. I have never had issues above 0F. As was stated, bio really spikes diesel with lubricity that was lost when we got LSD and ULSD fuel. A B2 blend will add back the lubricity lost going from LSD to ULSD, and a B5 blend will add back all the lubricity we have lost over the years.
One caveat with biodiesel. It has a little higher flash and vapor point than petro diesel. It has caused, in some instances, a slight fuel dilution situation to occur. One needs to watch things a little closer when using high blends of bio. There is always a little fuel that slips by the rings, and normally the internal heat will keep it in vapor and it will blow out or recycle via PCV. If temps do not run high enough in an engine, the bio can coalesce and build up in the sump.
Hey there, VA, what do ya say? How many vets did you kill today?