I started draining my antifreeze this afternoon in preparation to switching to Extended Life. The Prevost manual says the system holds 24 gallons. I assumed the Webasto would hold a couple gallons more.
I have drained all 3 of the drain valves on the engine and lines, removed the plug from the bottom of the radiator, disconnected hoses from the Webasto and the heater lines, and I still have only 18 gallons of fluid. I opened the heater valve to let the heater lines drain, and that didn't seem to work, so I removed the lines in several places and that caused about another gallon to drain out the rear of the bus.
I have collected all I could so I would know how much I have drained. I don't know where the rest of the antifreeze can be. I placed 4" ramps under the front tires and lowered the rear of the bus to assist in the draining, but I don't see where I am going to get another 5 or more gallons. When I haved drained all I can, I intend to flush the system a couple times by filling with water and draining again after I run the bus until the thermostat opens.
Any suggestions as to how I can get any more antifreeze out of the bus? Has anyone else done this before?