Hello, I (total layman in terms of cars) just got my E12 – meanwhile 130,000 km on the clock – from the customer service. It is leaking cooler. That means within two years the level of coolant (pink) dropped from Max. to Min….. they also gave the estimate. Complete: 600 €. Not very little…. As layman I would say… big leak can not be there…..if in 2 years – what I know – 3 liters of coolant escape.. At Amazon I have seen products like “cooler diggers” etc… Lt. the reviews does not seem bad. Ask the professionals: Let change or try with cooler poet and after 3 months look how much coolant escapes.