Coolant didn't completely drain

[bottgers]

I changed the coolant in my Corolla yesterday, but apprently not all of the coolant drained. I drained both the radiator and the block like the procedure in my Haynes manual called for, but to fill the system back up only took 1 gallon of coolant. The book says the system holds 6 quarts. Why didn't the other 2 quarts drain? According to the manual, there's only one block drain.

 

[oilyriser]

I did something like that the first time I ever changed coolant. I drained what came out, added 3L of pure antifreeze, then proceeded to top off with 3L of distilled water, to reach the system capacity listed in the manual. I reached full after only 1L. oops.

 

[Kestas]

I don't think you can get ALL coolant drained out of any car. The systems aren't designed to shed water by gravity from all the low points. That's why I drain, flush, then drain the water, the refill first with the specified amount of antifreeze, top off with water.

If you don't flush, then drain and refill with a 50% dilute mixture until full.

 

[Patman]

I just did a coolant change in my wife's Honda today actually. I never do a complete change though, nor do I bother with doing a flush. Ever since I bought this car new, my habit has been to drain the rad about every 6 to 12 months, and then refill it with a fresh 50/50 mix. I figure by doing it so often it'll never really need a complete flush.

A couple of times I've even done the procedure twice in a row (after driving the car to circulate the coolant and then letting it completely cool) just to try and get more of the coolant replaced.

 

[paulo57509]

I've always thought that the reason not all of it comes out is that a lot of it get's stuck in the heater core and its plumbing.

I just drain and flush a few times, add what ever anti-freeze works out to 50%, and top the rest off with distilled water.