Does anyone know how much, if any, coolant is left in the system when drained?

I have always found that a quart or more is always left that can't be drained without dissasembly.

I have always drained and flushed with plenty of water, then added enough antifreeze based on the coolant capicity to get a 50/50 mix by then topping off with water.

I will need to use distilled water in the Cummins. The tap water here is very hard, lots of calcuim. I could buy enough distilled at wally world at $.65 a gallon for the flush, or I could save the run-off from the house airconditioner.

 

when i blew most of mine out, there wasnt much left to drain. i didnt flush it(because it violently flushed itself) you could use air to try and remove all of it.