What are the main lubrication problems in passenger car engines?
• Low-temperature or light-duty operation. This is when a car makes a lot of short trips that never allow the engine to reach its optimum operating temperature. Partially burned fuel byproducts can result in sludge deposits and excessive rust. • High-temperature oxidation. Engine operating temperatures today are extremely high while the amount of oil in the sump is small, as little as four quarts. This severe heat stress on the oil can accelerate oil oxidation, resulting in oil thickening, loss of lubricating properties, varnish and piston deposits. • Passenger car engines deliver high horsepower in relation to the size and weight of engine components. This places great stress on engine parts such as the valvetrain, which strains to provide the high cam lift and spring loads required for efficiency and high engine speeds. The use of air-pollution control devices such as positive crankcase ventilation and exhaust gas recirculation can increase the heat stress on an oil and increase the
