How can E10 be detected in engine oil?

Year of publication: 2011


Since its market launch, the new E10 Otto fuel, a four-star petrol with a 10% ethanol content, has stimulated wide public discussion. The central focus is on its risk-free suitability for engines of certain types of vehicle. Especially at low engine temperatures on short journeys, this can lead to an increased introduction of E10 into the engine oil. Oil and ethanol are incompatible or do not mix. Excessive ethanol in engine oil could cause similar engine wear as excessive cooling water. At the same time, the engine oil becomes „thinner“. Due to the limited availability of this new fuel to date, not very much practical data is available to confirm these fears.

At the OELCHECK laboratory, a specially adapted investigation method is immediately available with which the proportion of E10 containing ethanol in engine oil can be specified. Since ethanol contains a significant amount of oxygen compared to conventional fuels, the GC method for chromatographic separation of oil and fuel, currently used to determine the petrol and diesel components in engine oil, is not suitable for E10. For the determination of the E10 content in engine oil, the ethanol component is ascertained with a head space gas chromatograph. The glycol content (antifreeze) described in detail in ÖlChecker, Winter 2010, was also measured using the same device and a similar method. With our investigation method specially adapted for the detection of ethanol, the oil sample is heated in a hermetically sealed container, whereby ethanol and petrol evaporate from the oil sample. Only this vapour is injected into the gas chromatograph. After separating all components contained in the vapour by means of a GC column, the ethanol content is indicated as a percentage. The petrol component is still indicated using the conventional GC method contained in the analysis kit 2.