1994 GMC Suburban Owner's Manual - Page 252

What Fuel to Use For best results, use number 2-D diesel fuel year-round (above and below freezing conditions)as oil companies blend number 2-D fuel to address climate differences. Numer 1-D diesel fuel may be used in below freezing weather, however, it will produce a power and fuel economy loss. The use of number 1-D diesel fuel in warm or hot climates may result in stalling, poor starting when the engine is hot and may damage the fuel injection system. Diesel fuel may foam when you fill your tank. This can cause the automatic pump nozzle to shut off, even though your tank isn't full. If this happens, just wait for the foaming to stop and then continue tofill your tank. A CAUTION: Heat coming from the engine may cause the fuel to expand and force the fuel out of your tank. If something ignites the fuel, a fire could start and people could be burned.help avoid this, To fill your fuel tank only until the automatic nozzle shuts off. Don't try to "top it off." Cold Weather Operation In cold weather (below 20"F, or -7"C), use 1-D or "Winterized" Number 2-D fuel (a blend of 1-D and 2-D). Be sure you get the right fuel. In very cold temperatures (when it stays below 0°F or -18"C), use Number 1-D. If you're drivingin very cold temperatures and can't get Number 1-D or a "winterized" Number 2-D, you can use one gallon of kerosene for every two gallonsof diesel fuel. Onceyou add the kerosene, run your engine for several minutes so the fuels will mix. Add kerosene only when the temperature falls below 0°F (-1 8"C ) ,because the fuel economy of kerosene isn't as good as that of diesel fuel. NOTICE: Never use home heating oil or gasoline in your diesel engine. They can cause engine damage. In cold weather, your fuel filtermay become clogged (waxed), especiallyif you use Number 2-D diesel fuel that hasn't been "winterized." To unclog it, warm the filterto between 32°F and 50°F (0°C to 10°C). You won't need to replace it. 6-6