Got questions? We’ve got the answers—Mondays when the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re offering up some winter performance tips for diesel trucks. S.M. • Ann Arbor, MI Q: I drive a 2001 Ford F-350 Super Duty Crew Cab pickup with a 7.3L Powerstroke diesel engine and a 4R100 automatic transmission. When the temperature drops below freezing, it seems to stop running. Between bad fuel filters, bum glow plugs, and water in the fuel, I just can’t get the truck out of the driveway! Once the temperatures warm up for a bit, it runs perfectly again. What’s the deal and what can I do to keep my Super Duty on the road? A: You’re not alone—diesel-powered trucks can be prone to these types of headaches. These problems are most likely caused by gel formation in the fuel. As ambient temperatures approach the freezing point, diesel fuel can begin to break down and “cloud.” The clouding is the result of paraffins in the fuel solidifying. As the outside temperatures continue to drop, the paraffin molecules combine to become solids in the fuel. This is known as the gel point. When this happens, the fuel filter becomes clogged and restricts or eliminates the fuel flow to the engine. Diesel fuel suppliers usually offer special winter formulations in cold-weather climates; however, there are a few other steps you can take to avoid reaching the dreaded gel point. To ensure your diesel fuel is for the cold, try treating it with an additive that’s formulated for winter conditions. The additive will lower the fuel’s gel point, thereby preventing the fuel from breaking down and clogging the fuel filter. You can also install an aftermarket fuel heater to maintain the fuel’s temperature above the gel point regardless of outside temperatures. One last area for concern is condensation of the fuel. Water in the fuel can further aggravate the problem of fuel gelling as well as corrode fuel injector nozzles. To prevent this, many people install water separators for additional protection.