I should say, "A word to someone wiser than me"

I left the maintenance garage this morning feeling good that all the fluids are fresh, topped off and I'm ready to get my new tires and hit the road with confidence. Just before leaving the driveway, I'm realizing that as cold as it is this morning, I should turn the heat on. I haven't had heat in the driver compartment since I bought the bus three years ago. Since then, I removed all the bus heat system and left only the driver area heat. So, I did what I knew was right, I went back and opened both gate valves to allow the coolant to flow to the front of the coach.
I know what you're thinking... Seriously, I had capped off the lines to the old heat unit. But, to be safe, I decided to check for leaks. After-all, it's been three years. No leaks. I go jump in the driver seat, turn on the heat and proudly slip into drive and away we go to the tire store. I got about ten miles before the engine shut down on overheat. Now, this is frustrating. I've got a freshly serviced coach and the thing leaves me dead on the road. (you know how hard it is to steer without the engine running?).
I soon realized that I didn't have any coolant showing in the site-glass. Then it hit me. When I opened the gate valves I dumped all the engine water and reserve into the huge copper lines and driver heater and didn't leave enough for the engine. So, my word to those wiser than me... remember to check your coolant fluids after opening the gate valves.
Fortunately for me, I was just around the corner from two different auto-parts stores. So, I picked up a couple jugs, dumped in a total of 4 gallons of water/coolant and continued to the tire store. Later today I guess I need to pick up a couple more jugs. The four gallons didn't get it back into the site-glass. So, I'm sure 4 more should do it.
At least I'll be sitting on some nice new rubber this time

Dave