Yes, they do that. Mine had a seep leak along the injection mold fill mark right on top. It's the long oval shaped bit that's kinda rough right on top. You may as well replace all the hoses while in there, because all that plastic has been subjected to the same heat cycles and pressure, and if it isn't leaking now it soon will be. When you order the new hoses, make sure to compare the picture to the one on the car because different cars had different cooling options, like an oil cooler that pipes through the rad hoses.