Originally Posted by CanadianSmokie

Yes, the RUG thins out the oil and also produces a chemical change to the oil so that it does not 'string' when pushed through the injectors. This will help avoid coking of the injectors and rings. It's also a good idea to add a cetane booster to the mix to help smooth out the combustion process.
Gas has been a winter additive to diesel for decades. It helps to thin it out and prevent clouding in the cold.