Good evening A week ago, SID reported: Check cooling water! When looking then found out that the liquid level is really in the area of the sensor for reporting in the balance tank. Well, 0.2L replenish cooler frost protection, so happened. 2 days ago then a small cooling water puddle in the garage. After a long search I then found that at the front of the heater / preheater coolant exits from a small opening (production) in the housing. Today everything is dry again and also the cooling liquid level correct. Should I worry about the heater? (Eberspächer D3WZ) Checking is a bit difficult in the current weather.