Synthetic oil in the winter is the best way to go! If you can take your battery indoors it helps tremendously. The remaining tip is to add regular unleaded gasoline to your fuel in really cold temps.[10+ F] in percentages spelled out in your owners manual under adding supplemental fuel. This prevents the parafin molecules in diesel fuel from bonding together and plugging your filters, better known as gelling.It also gives your fuel a little more pop!, but don't leave blended fuel in your tank in warm weather, it may not even start on it.