Humming Noise from 2015 MB E400


Good to know!
2015 Mercedes E400 makes humming noise after turning off the engine. Luckily nothing is wrong with the car, it comes from normal operation.

We found a few logical explanations, such as:
-The LED headlights have 2 fans in each light that run to cool the lights. Mercedes service can adjust the setting in order to shorten the operational time. Now they run when they are suppose to, when the lights are on.

- Obviously turbos run hot and the bearings in the units reside in a rather brutal environment and that becomes worse when the engine is turned off and bearings sit in oil that is cooking from the heat basically a turbo creates extremely high temperatures that will cause the lubrication in the turbo bearing housing to disintegrate. A way to avoid this situation is for the cooling oil to continue to circulate thru the turbo thus the humming noise of the turbo oil pump in action.