ASTM D3524 Diesel Fuel Diluent in Used Diesel Engine Oils by Gas Chromatography
During normal engine operation, small amounts diesel fuel may leak through engine seals and mix with engine oil. This may increase with engine wear. If excessive amounts of fuel mix with the oil, the performance of the engine may be compromised. This test determines the amount of diesel fuel in used engine lubricating oil. It is intended for SAE 30 oil only.
A known quantity of n-decane is added to the sample, and the mixture is injected into a GC to achieve a separation as per the method. Detection is by flame ionization. The mass percent of diesel fuel is calculated by comparing the diesel fuel peak with the n-decane peak (the internal standard) using a calibration curve. Reported is mass percent of diesel fuel.