Mercedes E280 does not start

By Start do you mean

A) it will not turn the engine over when you turn the ignition key or B) It turns the engine over but the engine won't fire?

It does not turn the engine at all. The starter has been checked. It is ok

From what you said where it would not turn engine over... it is the starter... your brushes are worn inside that when enigne is hot, it will not contact the starter... and when the starter cooled down... connection is made...

So change the starter.

I'd lean heavily toward the brushes/windings in the starter. Try this: next time the car won't start, turn on your head lights (or open the door and look at your dome light) and watch what happens when you try to start it. If lights fail to dim, that means no power is going to the starter. That means an open circuit in the starter. New starter time. If they dim to almost out (or are dim when you turn them on), chances are you need to get the batt/charging system cked. A loose batt plate will intermittently short and cause that problem. Having the starter tested cold tells you very little. Never underestimate the power of a loose battery post. Ck the easy stuff first.