It’s burping out the extra water it doesn’t need. Just monitor the level. As long as there is 1/2 to 3/4 inch over the top of the coils your fine.

If it’s truly leaking from under the valve cover try another 1/2 turn on the hold downs. If that doesn’t do it you may have a bad gasket.

Glad your making progress.


Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
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USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)