When the weather man predicted really cold temps (0 Farenheit) a few weeks ago, I started putting in a diesel additive and had no problems. I'm running straight diesel at start-up, then switching to WVO once up to temp on the road, and purging the system before shutting down...so that I'm back to straight diesel again for starting up the next time.

When I was driving the car every day, things were OK, but this week's snowstorm kept me off the roads for a few days and that's really when things got bad.

Haven't checked filters yet.