Bleeding air out from coolant
 

AR20.00-P-1142EWS Drain/Fill In Coolant: https://workshop-manuals.com/mercede...res/page_3122/ + next pages.

I changed the coolant in my 2011 E350 (drain and fill) and never had to bleed it. I seem to recall reading somewhere that it was self bleeding. Either way, I kept a close eye on the coolant level and temp gauge for a couple days and no issues at all.

We never vacuum fill them at the shop and never have issues. I have seen only one case, and it came from another shop so I don't know the reason, but on a GLK with a M276 it had an air pocket trapped and would overheat randomly, we vacuum bled it several times and it went back to normal. But every other time I've seen or done personally any coolant service or cooling system repair, we fill them full, run the heater, let it warm up and open the thermostat, then top it off after it cools, and it's perfect.

Pour the new coolant in , start the car , let it run for a few minutes on idle with the cap of , and then put it on and you good. It will bleed the air out by itself.

Interesting, but the WIS does NOT show using a vacuum bleeder for the M276. See attached.

Usually cars self bleed, more or less. There are always problem spots so you need to rev the engine and maybe even drive it a bit to get all the air out. One I have, not MB, that to get the air out I need to drive up a very steep hill and rev it. All the other cars I've had I simply rev it to ~3500 while topping it off and I'm good to go. If there are any little bubbles hiding they'll come out with some driving.
The fill reservoir is designed to exchange air for water so it will self bleed as you drive. Just fill it with water, then rev it and check to see how much air is in it. Then drive it and check again. The more aggressive you drive the more air it'll get out, and faster, if any is left of course.