BMW didn't seal the throttle after cleaning.

There is no need to apply sealant after cleaning the throttle. Generally speaking, it is recommended to clean the throttle every 20-40 thousand kilometers, but this is only a reference value. The specific cleaning cycle depends on everyone's car habits and car environment.

Throttle is a controllable valve that controls air to enter the engine. There are two kinds: traditional cable throttle and electronic throttle. After the gas enters the intake pipe, it will be mixed with gasoline to form a combustible mixture, which will be burned to do work. It connects the air filter and the engine block, and is called the throat of the automobile engine.