Originally Posted by
Tom3120
I had good warm heat before changing the pump. Wondering if I just don't have enough fluid in the system yet as I only added 2 gallon wich is almost a gallon short of capacity although the reservoir tank still is half full.
With so much missing there is probably a large air lock, those valves are more or less at the highest point in the system.
Is the header tank half full with water or old antifreeze?
Fill it right up with distilled water, run it and top it up again if required. I would then drain it all again which would remove more old antifreeze.Then do what you have to do to get the 50/50 mix. There is a good PDF by James1549 on renewing the antifreeze, you should read it.