Im really low on coolant and I just noticed its green? I know im supposed to have bmw coolant and I do have enough blue to fill up.. I just dont have the time to flush the radiator right now plus I have to replace soon because of a small leak on the bottom of the reservoir.. my question is can i just put some of the bmw coolant? would it be bad to mix it even if its that low? heres a picture to kinda show you how much green coolant ther is