I don't want bmw coolant.
I’m assuming BMW coolant is the same product as Mini-Cooper coolant. Please explain, why don’t you want to use it? Is it b/c it costs much more than aftermarket coolants? If so, and the owners manual doesn’t list the actual coolant specs requirements, visit a BMW dealership, ask them to show you a bottle of the correct coolant for your car, and write down the specs of their coolant, which is usually listed on the bottle. Then search for an aftermarket coolant that has identical specs.
You might wonder why the coolant specs are important. It didn’t use to be that way so much, all the typical cars you’d see on the road in the 1960’s could pretty much use any basic coolant you could buy at an auto parts store. But back then all cars used the same coolant gadgets and technology and same gasket material. These days, not so much. Gaskets can be made out of different materials, one car to the next. If you don’t use the right type of coolant it can damage the gaskets and you end up with coolant weeping out of the engine, or even worse, overheating and blown head gaskets. Likewise for the materials used to construct the radiator, passenger compartment heater, coolant hoses, transmission cooler lines, water pump, coolant temperature sensors, thermostats, etc.