I am having a problem with the truck losing antifreeze.
The heater core was leaking but I used K-seal and that
seemed to have corrected that problem.
I've changed the water pump as well because that was
leaking.
Now its not over heating anymore but the reservoir seems
to always be empty, there's no fluids under the truck and when
I crack the cap a little then it fills up again .. This happens even when the truck has been parked overnight and it not hot.

I do have an O2 sensor code that popped a few days ago and
I'm getting that fixed tomorrow but I don't think that would have
any effect on the reservoir or antifreeze.
There's no antifreeze (Milky look when I checked the oil) so I'm
"ASSUMING" it's not a cracked head so I'm at a loss on what to check
next .. Any suggestions would be GREATLY appreciated and THANKS in advance for any help!!