Diesel fuel quality should not be assumed. A simple rule to remember is if you get 1 gallon of bad fuel and add it to your tanks of good fuel, you just tuned your tank into bad fuel, according to Dieselcraft.The company added that testing of fuel on a regular basis will prevent surprises at the wrong time. Dieselcraft offers a new, fuel test available from its new web page www.dieselfueltestkits.com.Test #OX-20 will test for fuel oxidation, the company said. Oxidation starts to take place on fuel that is over 30 days old. The first signs are darkening of the fuel. The older and darker the fuel the less efficient it is. Eventually oxidation will lead to tank sludge and filter plugging. “This test is simple and shows results in less than 20 minutes,” according to Dieselcraft. “If the fuel is bad the test will indicate a black reaction layer in the test vial. No reaction is good any reaction need additives and extra filtering.”The Test kit consists of the oxidation catalyst, five test vials and the sampling pipettes. Each kit will do 20 tests, the company added. Dieselcraft also mentioned that the tests will work on all diesel fuels: #2 Diesel, Red Diesel, Maine Diesel and Jet Fuels.