Mine also has a "wetness" along the top seam that seems to come and go....sometimes I will check it and its moist along the seam on top, sometimes its dry....nothing ever drools out or onto the ground.....and it hasn't lost any coolant at all in the coolant tank...but when it is moist and I put it on my finger and rub it I can tell its definatley coolant. Later in the summer I will probably replace it, unless it fails before then

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)