I’ve been putting off replacing the heater core in Red Ryder (a ’98 Dodge Turbo Diesel) for a lot longer than I should have. I’ve been keeping a car blanket in the cab during the winter for a few years now. It generally takes about 30 miles at highway speed to bring the cab to a comfortable temperature when the outside ambient temperature is in the low-40s. I hadn’t observed coolant leaking in the cab…yet. On the return trip from Coeur d’Alene, Idaho, in January this year there were some…