ANALYSIS AND EVALUATION OF INTERNAL COMBUSTION ENGINE LUBRICATING OILS AVAILABLE IN THE EGYPTIAN MARKET

This paper presents an analytical study to evaluate the quality of most internal combustion engine oils circulating commercially in the Egyptian markets through shops and workshops for sale or oil change. This evaluation was carried out on various lubricating engine oils for local and imported brands with different viscosity grades. Fifty packages of gasoline and diesel engine lubricating oils were randomly collected from different types of local and imported engine oils. Three important physical properties of the tested oil samples, with three replicates for each sample, were measured. These measurements included kinematic viscosity (KV), flash point (FP), and pour point (PP), which directly affect engine performance and oil quality. Experimental results were compared with the requirements of standard specifications according to Egyptian, regional, and international standards to evaluate the extent of oil compliance. The results indicated that 26% of the total analyzed oil samples were found to fully match the standard specifications of all three measured properties. Among these compliant samples, 10 were imported oils out of the 31 imported samples, with a percentage of 32.25%, and six of these compliant samples were in oil grade SAE 50. None of the samples from grades 15W-40, 5W-20, and 5W-40 met all three standard specifications together. However, 56% of all oil samples conformed to two out of the three measured properties, and 18% of all samples matched only one property. None of the grade 5W-20 oil samples complied with the standard limits for kinematic viscosity.