Running Biodiesel In The Cold

If you’re planning on running Biodiesel in your diesel engine when it’s cold outside, here’s a few tips & tricks to help you keep everything running smoothly

1) Know The Gel Temperature Of Your Biodiesel

Biodiesel tends to gel up at much higher temperatures than diesel fuel. Because of this, it’s very important that you know the temperature that your own Biodiesel gels at so that you can plan accordingly.

Believe it or not, the kind of oil that you use make your Biodiesel from will have a big effect on what temperature the Biodiesel gels at.

For example, Biodiesel made from peanut oil tends to gel at relatively high temperatures (around upper 40’s to low 50’s) whereas Biodiesel made from canola oil or safflower oil can usually stay liquid clear down near freezing.

To identify where your fuel gels at, grab a glass jar, fill it with your Biodiesel, and set it in a refrigerator for a good 8 hours. Monitor the temperature during this time (a good pocket thermometer works great!) and watch your Biodiesel for signs of gelling up.

If your fuel doesn’t gel in the refrigerator, put it in the freezer and monitor it’s temperature every few hours while watching for signs of gelling. At some point, you’ll see it start to gel up. It usually starts at the bottom as a haze and then the haze thickens into a gel.

We usually keep a jar of the Biodiesel we make in a jar on top of a garbage can located outside in the cold. This way if the jar is gelled up in the morning, we know we’re pushing our luck running on the Biodiesel.

(Click here to see our Biodiesel cold weather experiment!)

2) If Possible, Park Your Diesel Vehicle In The Garage

While this isn’t a complete cure-all, it keeps the cold wind from blowing on the fuel tank while parked. Also, the temperature inside an enclosed garage will usually stay a bit warmer than outside. This slight increase in temperature can help to keep the fuel in the tank from gelling as quickly.

Also, if you can’t park your diesel in a garage, another trick is to place a lightbulb under your vehicle’s fuel tank and point the light at it (think halogen trouble lamp). You can also place an incandescent light bulb near your fuel filters as well for the same effect. The heat given off by the light bulb will help to keep your fuel tank or fuel filter warm which can help prevent the Biodiesel from gelling.

(TIP: If you do use a halogen lamp, be sure not to place it too close to the fuel tank; remember, they can get extremely hot, we just want to WARM the tank, not burn a hole through it.)

3) Keep The Fuel Tank As Full As Possible

A full tank of Biodiesel takes much longer to gel than half a tank and a half tank will stay liquid longer than a quarter of a tank will. It’s simple thermodynamics. A large body of liquid will retain it’s temperature longer than a smaller body of liquid will. So, keeping the tank as full as possible can help increase the time it will take for the Biodiesel to gel up on you.

4) Blend With Diesel Fuel Or Kerosene
Blending diesel fuel in with your Biodiesel will help lower the temperature at which it gels. You’ll need to experiment with your particular Biodiesel to identify which blend ratio will work the best, but if in doubt, add more diesel fuel!

A good rule of thumb is that if the temperature will be dipping below freezing, a 50/50 blend is a good place to start. We usually can get away with a 70% Biodiesel/30% diesel fuel blend using canola based Biodiesel throughout the majority of our Utah winters. Temps here usually are in high 20’s to low 40’s during most of the cold months and occasionally can dip down into the teens.

Our rig, a 2003 Ford 7.3 diesel, is parked in a heated garage at nights, but sits out in the cold all day long. If we know it’ll be in the teens, we usually increase the diesel fuel percentage to about a 50/50 mix. If it’ll be down below zero, we don’t even bother using Biodiesel (it’s not fun getting stuck on a freeway with a gelled up fuel tank when it’s that cold outside).

Also, if you plan on blending, add the diesel fuel to the tank FIRST; then add the Biodiesel. We learned this trick years ago and have found that it helps the diesel fuel to blend with the Biodiesel much better. Another trick is to immediately drive the vehicle for a while after be blend the fuel in the tank. The motion of the vehicle helps to slosh things around in the tank & gets everything well mixed.

5) Use Biodiesel Anti-Gel Additives
While there aren’t a lot of great anti-gel additives for Biodiesel available, there are a few that we’ve heard work alright. The problem is in the actual chemical make up of Biodiesel itself. Turns out it’s REALLY hard to keep the crystals from forming that cause fuel gelling in Biodiesel. It’s possible to slow them down, but once they get started, it’s next to impossible to stop them from continuing to form.

Two additives that we’ve seen do marginally well are:
A) Amsoil Cold Flow Improver and
B) Technol B100 Biodiesel Cold Flow Improver

While both of these additives can help, diesel fuel, or good old kerosene, tend to work much better.

6) Get To Know Your Onboard Fuel Filter

Fuel filters with smaller micron ratings tend to gel up quicker (ie. 5 micron or smaller) than larger micron fuel filters. Also, smaller fuel filters can gel up faster too.

The location of the fuel filter can also play a role. If it’s hanging down low on the vehicle where the wind & elements can get to it chances are it’ll gel up faster than a fuel filter mounted right up near the engine. If possible, insulate your fuel filter! Even some cheap foam insulation or foil bubble-wrap can help.

Also, always pre-filter your Biodiesel through a fuel filter with a micron rating equal to or less than your on board fuel filter. If possible, pre-filter the fuel at ambient air temps too! This will help filter out the junk plus, it can help filter out some of the thicker particles that tend to plug up on board fuel filters. It’s always better to plug a pre-filter in your garage than it is to plug your on-board fuel filter on the side of the freeway.

We carry 10 micron fuel filters in two different styles to help you accomplish this task. A cartridge style GPI branded fuel filter and the ultra cool Goldenrod clear bowl fuel filters.

7) Install A Fuel Heat Exchanger

One of the cool ways to keep your Biodiesel from gelling up while driving on a cold day is to install a heat exchanger. These work by exchanging the heat from engine coolant through metal tubes to heat up tubes with Biodiesel flowing through them.

While this won’t work immediately on start up, once the engine is up to temperature, your Biodiesel will stay nice & toasty warm as it flows through the exchanger. It’s best to install the heat exchanger before the fuel filter to keep the filter nice & warm and free of gelling fuel. Click here for an example installation diagram

We’ve heard great reviews from people using our SpringPro 250 Heat Exchanger and find it to be a great tool to keeping Biodiesel from gelling.

8) Install A Fuel Filter Heater

If you’d like to have almost instant heat when you start your diesel, then you can install a fuel filter heater!

We offer both a coolant heated fuel filter mount as well as electric fuel filter heaters that can deliver heat almost instantly to a fuel filter. These are extremely popular among Biodieseler’s and work extremely well! The electric heaters can be wired to a switch and come in two sizes to fit most fuel filters available. In tests performed by our customers, they have been found to be extremely effective at allowing the fuel to flow through the filter without gelling up. If it’s super cold outside, you can leave the heaters on while you drive or if you just need a burst of heat initially, they’ll do the trick quite well!

So, there you have it, 7 ways to keep you running Biodiesel in the cold! Happy travels & keep warm!

Graydon Blair
Utah Biodiesel Supply

About Utah Biodiesel Supply

Utah Biodiesel Supply is an industry leader in offering innovative ways to empower our customers to produce Biodiesel. From free online instructional videos on how to get started making this great renewable fuel to promotional items to help our customers proclaim their energy independence, Utah Biodiesel Supply has it covered. With the widest selection available of Biodiesel equipment, supplies, and promotional items, you're sure to learn something new about Biodiesel every time you visit.

3 comments on “Running Biodiesel In The Cold

  1. Good article. I’ve been running biodiesel in cold weather since 2008, in VW TDIs and my old Toyota 4 cyl truck. It’s colder here in Alberta than Utah, minus 30F occasionally With an average winter temp of maybe +10f or so. Today I’m running 20% biodiesel. Around freezing temps I run B50. If we get a cold snap I go down to B10. Above 40f I’ve never had a problem with B100.

    This is with canola based biodiesel.

    I have a 12v electric filter like the ones above that works great. I only use it when very cold or if I get caught with too high a blend in a cold snap.

    By the way, when is the u.s. going to join the rest of the world (95% of world pop) and switch to metric?

  2. I mean 12v electric heater not filter! Speaking of filters I filter my fuel thru a 10 micron farm filter then thru a 1 micron home water filter as it goes in the tank.

    Also I get a kick out of those from warm climates like Texas worrying about gelling. They talk about 40-50f being cold and think their fuel will turn to margarine! It won’t – you can run 100% biodiesel all day long in those temps!

  3. I run B100 pretty much all year in two 7.3 fords. I also blend with k-1 if temps. are below 30 degrees. The ratio of 5Gals k-1 to 25-30 gals B-100 seems to work pretty good. I live in central Illinois and we have a pretty wide temp. swing at times.

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