An engine oil flush is not absolutely necessary for most cars, but it is beneficial in instances in which there is a significant possibility of carbon deposit build up. When large amounts of carbon build up in the oil system, the car's oil cannot flow as intended, which leads to serious engine problems. If the oil is changed regularly, however, the gunk in the car's oil system usually does not have enough time to build up to a harmful level.
An engine oil flush is a process in which a service technician adds chemicals to the oil so that any carbon deposits in the oil system flow out of the system and into the oil filter. The technician then drains the oil and chemicals, replaces the oil filter and fills the car's oil reservoir with clean oil.
Auto technicians often recommend engine oil flushes as part of your car's routine maintenance, but regular oil changes make this service unnecessary. Consider performing an engine oil flush only if the car's oil hasn't been changed on time, the car hasn't been used for a long period of time, major engine work was done to the car or or a used car has been bought without any records regarding recent oil changes.