Originally Posted by Hook'em_Horns! View Post
Anytime you open up the system and refill, there's always a small amount of air left that will purge as you drive. Service will burp and fill as much as they can.
It's quite common to have to add a bit of coolant the next day or so as the level stabilizes.
Actually the problem is compounded because the air gets introduced and then subsequently trapped down low on the engine because that's where the heater is located.
If you're just filling up an open container then air wouldn't be getting trapped. Unfortunately it's all the twists and turns of the plumbing that causes air to get trapped.
“Insanity is doing the same thing over and over again, but expecting different results.” - Albert Einstein
2017 2500HD GMC Denali CCSB