May I use RV antifreeze in my car's radiator?
What about in a toyota, which, when it comes to auto antifreeze, insists on the red (iirc) stuff?
When I go away in the winter and want to turn my heat off, I buy a gallon of RV antifreeze and put it in the traps of the sinks, shower, bathtub, toilets. Last time I had about 1/10th of a gallon left over and it's not enough for next time, if there is one, so what is something worthwhile I can do with it?