Diesel Exhaust Fluid & Engine Heating


Hi, I am Mike Moore, a Ford Certified Diesel Technician at Lasco Ford in Fenton.  I was lucky enough to

have the opportunity to answer some great questions from local people regarding their diesel trucks, and I think they really are some great subjects.  I hope that the answers I am providing below help you with questions you may have with your diesel truck.

I heard a friend talking about diesel exhaust fluid for his pickup truck. Is diesel exhaust fluid real or just another fictional automotive term like muffler bearing or kanutin valve?   Larry from Linden

Well Larry, unlike muffler bearings and kanutin valves, diesel exhaust fluid (DEF) is the real deal. As government regulations on automotive pollutants have gotten more stringent, automotive engineers have been forced to become more creative in their attempts to reduce vehicle exhaust emissions. DEF is made from deionized water and urea; certainly, diesel exhaust fluid is a better sounding descriptor. Today’s diesel engines run on a very lean fuel to air mixture to reduce soot and minimize the amount unburned fuel escaping the combustion chamber. This high volume of air increases the levels of nitrogen oxides, another harmful pollutant, expelled into the exhaust streams from the engine. The DEF solution is stored in a holding tank and minute amounts are injected into the vehicles exhaust system where a chemical reaction takes place converting the oxides into nitrogen and water. So, DEF performs a valuable function in helping diesel engines run cleaner. The DEF solution should be replenished periodically, having the fluid level checked during regular maintenance services is recommended.

Now that winter is fast approaching is there anything I need to do to my diesel engine F-150 to prepare it for the sub-freezing temperatures?  Jeff from Fenton

Good question Jeff. The biggest concern with diesel engines in the winter months is the threat of fuel gelling and the myriad of drivability problems that can result. Fortunately fuel distributors change over to winter blends as the temperatures drop and fuel related problems are not a frequent occurrence. Still, it is a good idea to buy your diesel fuel from a high volume station that rotates stock frequently and not allow fuel levels to near the empty mark in your tank. An engine block heater is a great accessory that is easily installed on diesel engines to help them start on cold winter mornings. Many engine models come with block heaters installed from the factory; have a service technician inspect the vehicle, locate the cord to the block heater and make it accessible near the grille or front bumper for easy extension cord hookup on those bitter cold nights. Like all vehicles preparing for winter, make sure your engine coolant is topped off, appears clean, and has been changed based on the extreme driving condition recommendations listed in your vehicle owner’s manual. Have the battery checked, replace it if it registers anything less than fully functional. Getting stranded on a cold winter night is not worth the risk of saving a few dollars trying to stretch the life cycle of marginal battery.