Quick help coolant flush

i just completed a coolant flush and I'm trying to burp the system. I'm trying to bring my engine temperature up too 180 I believe to open up the block so I can burp it fully. I have the truck running 15 mins or so in the shade... It's still not taking much more coolant... Do I just have to wait longer or do I have a problem? So on my iPhone.

 

Can I rev up my truck too 1.5 rpm? To help get it to temp?

 

Yes and the higher flow will help get the air out. As picky as there trucks are you may also have to drive it for a while to totally eliminate it from the system. Good Luck.