after several weeks my dealer has agreed that topping up coolant every week is not standard..!!
They were not keen on fixing this;
A. I was overfilling the coolant reservoir.!!! not that anyone ever saw me do it..
B. "They all do that ... Sir.." !!
At last a mechanic doing the annual service said it was not right, and he wanted it back in when the parts had arrived.
sense at last..
This seems to be a known problem to BMW with the 310 my dealer mentioned it to me that he has replaced a few seals in water pumps already and he wanted to check mine. Took in in for a service and found a small drip. They replaced the seals in the water pump under warranty.