1998 ML320, 1975 280C
Sort of. The clutch will allow the fan to turn slower than the engine speed when cold, but should lock up to engine speed when the air passing over it gets above a certain number, lets say 190F. It will actually start to spin faster as the temp goes up. I'm not up on the 380's, but if it has an electric fan that will go on when the AC is on, and when the engine temp is above 200F.