How to un-gel diesel in a tank, filter, or tractor
Start with the filter: it's usually what's plugged, even when the tank still pours. Warm the system safely, add an emergency re-liquefier made for gelled fuel by its label, and once it's flowing, treat or blend the fuel so it doesn't gel again. Never use an open flame, never add gasoline, and never run without a filter.
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Wax or ice?
Two different things stop diesel in the cold, and they look alike. Wax forms when fuel drops below its cloud point. Ice forms when water in the fuel freezes in the filter. "Ice and wax plugs look the same, and sometimes it's both" (CRC).
| Clue | Points to |
|---|---|
| Cloudy fuel in a sample jar that clears when it warms up | Wax |
| Water on the tank bottom (check with water paste) | Ice |
| The tank is liquid but the filter or line is blocked | Either; fuel can gel in the line or filter while the tank is still liquid (CRC) |
Emergency products such as Power Service Diesel 9-1-1 are made to reliquefy gelled fuel and de-ice frozen filters, so they cover both (Power Service).
Field note: On gelled-fuel calls, the problem is usually in both the filter and the tank.
Bulk tank or dispenser: step by step
Field note: On a gelled bulk tank, the first thing I do is pump the water out, flush the system, and change the filters.
- Swap the dispenser filter. A plugged filter is often packed with wax or ice. Put on a fresh one and watch whether it plugs again (CRC). Never bypass or remove the filter to keep fuel moving; that sends dirt straight to your engines.
- Treat the tank with an emergency re-liquefier. Follow the label rate for the tank's gallons. Power Service's label rate for Diesel 9-1-1 is 80 oz per 100 gallons (label directions; Power Service). For a 500-gallon tank, that's 400 oz, a little over 3 gallons. Diesel 9-1-1 on Amazon.
- Warm what you can, safely. A tank or filter heater, heat tracing on short lines, or a heated building for portable tanks (CRC). Never use an open flame or a torch on a tank, pump, or fuel line.
- Let the tank come back above its cloud point before you trust it. Wax that settled to the bottom leaves the fuel uneven until it redissolves, so what comes out changes as the level drops (CRC).
- Check for water. Stick the bottom with water-finding paste and drain any water. Routinely draining water bottoms is the best defense against ice (CRC). See water in your diesel tank.
- Fix the fuel for the rest of the winter. Add an anti-gel (Power Service), or blend in #1 diesel. See below.
Tractor, truck, or equipment that won't run
- Get it warm if you can: a heated shop, or plug in the block heater and give it time.
- Treat the fuel filter. Diesel 9-1-1 is made to melt ice on contact when it's added directly to a plugged fuel filter (Power Service). Follow the label directions for your equipment.
- Treat the tank at the label rate, so warm, treated fuel is what reaches the filter once the engine runs (Power Service).
- Then treat with a regular anti-gel so it doesn't gel again (Power Service).
Stop it from happening again
- Add anti-gel before the cold. It has to be in the fuel before wax starts forming (CRC). See winter diesel additives for treat rates.
- Blend #1 diesel for deep cold. Cenex's schedule: below 35°F, about 70% #2 and 30% #1 plus an anti-gel; deeper into winter, 30% #2 and 70% #1; below −30°F, straight #1 (Cenex). Additives alone typically protect to about 0°F (Cenex).
- Protect the filter and short lines with a filter heater, insulation, and heat tracing (CRC).
- Watch out for summer fuel. Diesel bought in summer or early fall won't have the cloud point of fuel made for January (EPRI).
For cloud point, CFPP, and why bulk tanks gel first, see diesel gelling: when it happens and how to prevent it.
What to keep on hand
- An emergency re-liquefier: Power Service Diesel 9-1-1 on Amazon
- Spare dispenser and equipment fuel filters: Fill-Rite filters on Amazon
- Anti-gel for the rest of the winter: anti-gel on Amazon
- Water-finding paste: Kolor Kut paste on Amazon
FAQ
Will regular anti-gel fix fuel that already gelled?
No. Anti-gel has to be in the fuel before wax forms (CRC). Use a product made for gelled fuel, then add anti-gel so it doesn't happen again (Power Service).
Can I add gasoline to thin gelled diesel?
No. Gasoline lowers the flash point and creates a fire hazard. Blend with #1 diesel or a kerosene-type fuel instead (EPRI).
How do I know if it's wax or ice?
You often can't by looking; ice and wax plugs look the same, and sometimes it's both (CRC). Cloudy fuel points to wax. Water on the tank bottom points to ice. Emergency products like Diesel 9-1-1 are made to handle both (Power Service).
Sources
- Coordinating Research Council: Diesel Fuel Low Temperature Operability Guide (CRC Report 671, 2016)
- Power Service: Diesel 9-1-1
- Diesel 9-1-1 label directions (Agro Trade Parts listing)
- Cenex: Diesel gelling and how to stop it this winter
- EPRI / Southwest Research Institute: Winterizing Diesel Fuel (TR-104843, 1994)
Product rates are the makers' own; follow the label on the product you use. This guide is general information.