[m240nj]

So I have an ongoing saga that began over a year ago. I leased my 2017 m240 in November of 2017. 9 months into owning the car, the coolant light came on. No big deal, figured it was low from the factory. Went to my local dealership and they topped it off. About 4 months later, it comes on again. I go back to the dealership and they tell me nothing to worry about, it's a known thing that the B58 needs to be topped off once or twice towards the beginning of ownership. In September of this year, it came on again. This time, I told the dealership I was concerned and they took the car in to inspect. They checked everything and said it was fine. Once again topped off the coolant. About 2 weeks ago, the low coolant warning came on again. This time, I told them something HAS to be wrong and they stated it was likely just because it was winter time. They kept the car for 2 days and preformed pressure tests. Once again, they return the car to me stating it's perfectly fine. As soon as I leave the dealership, I hear some kind of electric motor sound coming from the engine bay area and it comes on every 30 to 60 seconds. I drove the car for 2 days and continued to hear the sound which I had NEVER heard before. I drop the car back off again yesterday and tell them about the sound. Today I get a call saying the radiator was damaged by a rock, is spraying coolant out and needs to be replaced for $1,600. The CSA says he has no idea why it wasn't found previously since it passed pressure testing 1 week earlier. I expressed to them for a long time that coolant shouldn't be disappearing. I went to the dealership tonight to see the vehicle. I'm not an expert by any means but the radiator appears to have normal wear on it with no significant damage at all. Before I brought the car to them a week ago, it was never spraying coolant and was not making the sound. They said the sound was due to air getting into the system from the leak. They also told me the car is now undriveable. The coolant light wasn't even on when I brought it back in so no way it was losing coolant that fast. Furthermore, they're telling me if they replace the radiator, I MUST pay for a new mesh part (which didn't come with the car) that protects the radiator. They said they won't perform the work without installing it. The CSA told me to file a complaint with BMW corporate about the mesh not coming with the car to try to get it covered by warranty, which I did this evening. Looking to get some opinions on this. Does the damage look significant enough to cause this? Should this be under warranty since the car didn't come with the protective mesh insert that they now force you to buy? Thanks everyone.