Add Howes Diesel Treat to the tank right before you fill up, matching the dose to the outside temperature.
Howes Diesel Treat prevents fuel gelling in cold weather, but only when you dose it correctly and at the right time. The most common mistake is pouring it in after you’ve already fueled, or waiting until the tank has started to gel. Whether you drive a heavy-duty truck, a tractor, or an RV, the same rule applies: measure the dose, pour it in, then pump the diesel on top so everything mixes.
What Does Howes Diesel Treat Do?
Howes Diesel Treat is a winter-focused diesel fuel conditioner and anti-gel additive. It lowers the temperature at which diesel fuel forms wax crystals, keeps those crystals from plugging your fuel filter, and adds lubricity to protect the fuel system.
The product also works year-round to clean injectors, remove water, reduce smoking and rough idle, and prevent deposits. Howes states it is safe for all diesel and biodiesel blends, including ULSD, and it contains no alcohol or harmful solvents, making it particulate filter friendly.
How to Use Howes Diesel Treatment: The Step Order That Works
Using it correctly comes down to three things: timing, order, and dose.
- Start before the cold arrives. Howes advises treating your fuel before it reaches its cloud point — the temperature where wax crystals start forming. Begin as temperatures drop into the 40s°F, not after the first hard freeze.
- Pour the measured dose into the tank first. Add the correct amount of Howes Diesel Treat to the tank before you start pumping diesel. The fuel rushing in does the mixing for you.
- Match the dose to the temperature. The standard rate covers normal winter protection; the stronger rate is for below-zero or overnight sit conditions. The table below shows the two rates Howes documents.
| Temperature | Treatment Rate |
|---|---|
| Above 0°F | 1 oz per 5 gallons (standard rate) |
| Below 0°F | 1 oz per 2.5 gallons (strong rate) |
For larger tanks, Howes also documents a 1/2 gallon to 320 gallons above 0°F and a 1/2 gallon to 160 gallons below 0°F. Always follow the ratio printed on the bottle, since the dose varies by product and temperature.
When Should You Use Diesel Treat?
Howes’ guidance is clear: use anti-gel before the fuel reaches its cloud point, then keep using it all winter whenever freezing temperatures are possible. Howes notes that warm-weather Diesel Defender is the product for warmer months, and you should switch to Diesel Treat when temperatures start dropping into the 40s°F.
One dose treated fuel that sits overnight in freezing conditions may need the stronger below-0°F rate. If you’re storing the bottle itself, keep it at room temperature when possible, and at minimum avoid storing it below 20°F. If you’re comparing winter fuel additives before you buy, our roundup of the best diesel winter additives breaks down how the top products compare.
Storing Howes Diesel Treat
Proper storage keeps the product effective. Howes recommends keeping anti-gel at room temperature whenever possible, and never letting it sit below 20°F. The official SDS page is the reference for handling and safety, and a California Proposition 65 notice for ethylbenzene applies to the product.
References & Sources
- Howes Products. “Diesel Treat Antigel Diesel Fuel Conditioner.” Official product page with temperature-based dosing ratios.
- Howes Products. “Anti-Gel for Diesel Trucks: How and When to Use It.” Official guidance on timing, dosing, and storage.
- Howes Products. “Safety Data Sheets.” Official safety documentation for handling and hazards.
- Howes Products. “Diesel Treat Product Page.” Confirms compatibility with diesel, biodiesel, and ULSD fuels.