AbstractChemiluminescence is reviewed as a method of characterising different behaviour of lubricating oils. This includes mineral oils containing additives such as zinc dialkyl‐dithiophosphates, sulphonates, succinamides. alkylphenols and polymers. Using a chemiluminescence apparatus and manometric apparatus, various lubricant oil fractions blended with additives were examined. The basic emitters of chemiluminescence are excited carbonyl compounds, and results are presented showing the measurement of chemiluminescence at elevated temperature