The use of diesel engines at low temperatures is greatly complicated by filter plugging due to formation of wax crystals in the fuel. The usual method to prevent this filter plugging has been to lower the cloud point of the fuel by adding large amounts of kerosine. However, the expense that this represents and the alternate demands for kerosine make other solutions very desirable.New additives are becoming available which can aid in low temperature filterability and help with the plugging problem. In this paper, the Low Temperature Flow Test is used as a laboratory measure of the effectiveness of additive treatment for several dual purpose fuel oils. These results are compared with cold start data taken from vehicles which were cooled inside refrigerated trailers. The results indicate that the Low Temperature Flow Test is a conservative predictor of low temperature flow in actual vehicles, but is a less restrictive predictor than is the ASTM D2500 cloud point.