Coolant hose was rubbing on the drive shaft and at 4,931 miles the coolant hose failed and the vehicle lost all coolant from the system. Fortunately the hose failed after the car was driven into our garage and not on the open highway. We had just returned from a 1,000 mile trip to Nashville, TN from Winston-Salem, NC. This is a PHEV and the coolant also effects the temperature of the EV batteries. This was a improper installation of the coolant hose. I have attached a picture that I took of the hose showing the rubbing on the drives shaft. I have also included a copy of the repair to the car that is properly installed. The repair was done under warranty. The vehicle had to be towed and according to Mercedes service department was not drivable even though the EV battery was fully charged.