You'll definitely want to be blending then. At that temp I would be running no higher than B20. I've always played it safe when temps start dropping, because I've had gelled fuel and there isn't much you can do to get the car started with gelled fuel. The only solution is heat, either wait it out, or adding electric head or moving the car to a heated garage. When temps start dipping below freezing at night I always switch to about B50. Then when temps start hovering around or dropping below freezing all day then it's B20 or less.

You can experience hard starts with cold biodiesel. It gets thick and doesn't flow as well. So even when it's not gelled it can be a little harder to get the car to start on those cold mornings. Blending solves this issue.

The bottle necks for gelled and thick fuel are the fuel lines and the fuel filter. The tank is more resistant to gelling because of the volume of the fluid in the tank, and it's somewhat sheltered, being in the trunk.

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