I just recieved a email from cummins themselves they stated that it is not nessesary!! to add a fuel additive for the winter because it affects the cloud point of the fuel they are saying the same thing as the manual so it is not a definite yes or no but some one at cummins has to know I will call them this week and see what some else cummins has to say if all these additives aren,t nessesary Howes Winns Racor stanadyne Syn power approved for cummins ETC would all be out of business all these companies are repuatable And all these additives are USLD compliant so what gives? Matt 2007. 5 4x4 dually Laramie brilliant black leer cap Mbrp cool dual s putco door handles bores tailgate and door handle trim go rhino ss hitch step factory bug shield lund bumper grill insert putco punch grill