Oil is preheated to 130 degrees, and this temperature is maintained throughout the test to ensure consistent viscosity. The oil is filtered three times, first with filter media in the oil catch tray, second with a 5-micron filter, and third with a 25-micron filter. Oil pressure is recorded and compared to our standards for the engine type. The oil pressure recorded on your inspection envelope is metered for control reasons and will not relate to the operating oil pressure once the engine is installed in the vehicle.