Here is a cooling system "unsolicited tip"
Way back in the day I was working on a Mercury Sable? ( cant remember exact model, but it was a Ford).
Well anyway they were famous for getting an "air pocket" in the block somewhere when you serviced the cooling system, causing an overheating condition.
Supposedly you had to lift the front of the car like 20 degrees, spin around on your head 3 times, then shake a "magic chickens foot" at it, while chanting magic incantations, in order to get the air pocket out.
Or you could buy a "vacuum filler".
This tool turned out to be awesome when servicing just about any cooling system.
No spills, no waiting forever for the thermostat to open and antifreeze spilling out......
Just hook it up, draw a vacuum using shop air, then stick the tube into your antifreeze bottle and it sucks up the perfect amount of juice every time.
Never over-fills/spills and eliminates any possible air pockets that could develop, and has worked on every cooling system I have worked on to date.
(although I avoid working on cooling systems like the plague, due to the fact that getting ride of antifreeze is harder than trying to get rid of used Plutonium around here....Why is that????)
https://www.amazon.com/gp/product/B0002SRH5G/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1