I was only able to drain and refill about two and half gallons.
I still have the half gallon sitting on the shelf.
Good enough for me, I'll do it again when I hit 50K
If you have the stock thermostat it won't open till the engine gets to full operating temperature which is 195 degrees.
That's why I remove the thermostat to empty, it makes the job a little faster.
I also ran the engine for like 30 seconds a few times to make the water push a little more fluid out.
Your going to have to leave the cap off till it gets hot enough, you'll know when the thermostat opens.
There's air trapped in the engine now it's going to take some time to fully fill it again.
And it won't completely get all the air out.
That will happen after a few or more days of driving, just keep filling the overflow tank to the top line when you see it low.
As the engine gets hot it will push the air out though the cap and when it cools it will draw coolant back in.
It does that when getting on it too, it's just a slow process.