Why is there oil in the accelerator of a car?

It's normal to have oil stains on the accelerator of a car. But different types of machines will produce different degrees of oil marks. There will be oil marks at all throttle positions of turbocharged engines, which is the inevitable result of the design structure. However, some throttle positions of naturally aspirated engines will have oil stains, and some will not. This is related to the design position of the throttle. Forget turbines and naturally aspirated engines. Let's talk about how the oil came from. Throttle or intake. First, because of the oil return pipeline of crankcase ventilation system. Simply put, the gasoline vapor separated from the cyclone separator will be mixed with some oil vapor. These oil and gas are discharged back into the intake manifold and then burned. It is recorded that this oil will form traces in the intake manifold. A small amount of oil and gas contained in the crankcase ventilation system and the discharged oil and gas form oil traces in the intake manifold, and over time, a small amount of sludge will form in the intake manifold. Therefore, whether it is a turbocharged engine or a naturally aspirated engine, there will be more or less oil residue in the intake manifold. For naturally aspirated engines, there is oil in the throttle, which will inevitably leave traces of oil in the intake manifold. However, the engine oil at the throttle of turbocharged engine is more likely to accumulate in the intake manifold. In addition to the design structure, temperature is also one of the reasons for the formation of oil traces in turbocharged engines. After cold start at low temperature, oil will leak in the middle of turbocharger. This will pass through the throttle and air intake, resulting in the leakage of dirty oil in the middle. Therefore, the turbine car should not idle as much as possible, which can reduce the possibility of oil leakage caused by pressure drop after the turbine. In short, no matter what type of engine, after a period of use, there will be oil stains on the intake pipe and throttle. Therefore, it is necessary to clean it regularly, especially the turbocharged engine needs timely maintenance.