Complete Auto Repair
Engine oil is a type of liquid oil used for lubrication by various types of internal combustion engines. While the main function is to lubricate moving parts, motor oil also cleans, inhibits corrosion, and cools the engine by carrying heat away from the moving parts.
In engines, there is inevitably some exposure of the oil to products of internal combustion, and microscopic coke particles from black soot accumulate in the oil during operation. Also the rubbing of metal engine parts inevitably produces some microscopic metallic particles from the wearing of the surfaces.
Such particles could circulate in the oil and grind against the part surfaces causing erosion and wear. The oil filter removes many of the particles, but eventually the oil filter becomes clogged. The motor oil and especially the additives also undergo thermal and mechanical degradation.