Winterizing your diesel fuel system

Diesel fuel solidifies in Winter weather. You may experience an inconvenient, expensive engine shut-down unless you take preventative steps! Diesel fuel contains paraffins, similar to the wax candles are made from.

When the paraffin cools it solidifies into a light yellow or white wax, plugging fuel filters and choking your fuel system. Water in fuel can be a problem at even mild winter temperatures, causing a problem of ice formation in the filters. If it seems like you’ve seen, heard of, and even experienced more of these problems recently than in years past, you’re right. The new legal requirement in North America that diesel fuel be processed to limit its sulfur content dramatically affected the fuel chemistry. We’ve seen higher concentrations of water in fuel, too.

Many companies have reformulated their products to address the low sulfur fuel chemistry. Such reformulations typically include increasing the water-dispersion chemistry and adding a broader range wax modifying package. Penray’s version of this technology is trademarked “HAFI” for Hybrid Antisettling Flow Improving technology. This chemistry both retards wax crystal formation and disperses the tiny wax particles in the fuel to optimize filterability. The effectiveness of the technology is reflected in dramatically improved cold filter plug point and customer satisfaction experiences.


1. Dry out the system:

Before the hard Winter sets in, dry your fuel system with a water-removing fuel additive such as Penray Nox-Ice. These are very inexpensive, Isopropanol additives that remove any existing water from your fuel system. Make sure that your tank is at least one-half full and pour in a quart of Nox-Ice.

2. Change the fuel filter:

Install a fresh, clean fuel filter. An old fuel filter will plug much faster than a new one.

3. Use a Winter additive:

Treat your fuel with Winter fuel treatment, such as Penray Winter Pow-R Plus. These products address both water and wax in the fuel. They are inexpensive and effective cold weather aids.

4. Carry an emergency treatment.

If you follow the above steps you won’t likely need it, but you’ll come across someone on the side of the road that does! Penray Winter Thaw Emergency Diesel Fuel Treatment thaws gelled fuel and prevents fuel re-gelling/waxing with a pour point depressant/wax crystal modifier. It restores fuel flow and stops fuel icing via isopropanol and a water dispersant.

5. Inspect fuel lines and heaters.

Check your fuel lines and heaters for proper operation and blockages. If you have separate fuel lines to your heater, consider that it has been off all Summer. It is wise to check it out.