I totally understand what you are saying. The reason this came up is that hopefully in not too long time I will try to connect the heater core and then need to add some fluid. Now, the car has been going in the Los Angeles are without air condition, and I was thinking maybe that was the reason it was disconnected. But it might be a leaking heater core too. And if the leak is very small, I might end up trying something like bars leak or whatever to seal it. Or get the heater core fixed. And then we'll, the system needs to be flushed and new coolant put it. However, a good flush could be a smart thing in any case. When it comes to mixing coolant types I have a "reputation" for just adding up water if I don't have the same brand that is on the car.
Bill
