Well, My 2014 B-Class is on its 3rd motor in only 40,000 miles.
1st motor replacement was caused by the motor being flooded by coolant fluid.
The interesting part is that the vehicle continued to run.
The only problem I noticed was a very slight hesitation when beginning to accelerate, otherwise no other issues.
I took my car in when the service immediately message appeared. After discovering the fluid in the motor, MB decided to replace it.
2nd motor was replaced after only 1500 miles for the same reason. MB still has no idea what is causing this problem.
MB currently has their engineers working on it.
Has anyone had any similar issues?