Coolant loss white plugs

[72c20customcamper]

I am loosing a small amount of coolant on long trips . Used about a pint in 2500 miles . Pulled the plugs both 2 and 4 have white deposits . Truck is not overheating and runs fine with no smoke from exhaust . Did a co2 test on the coolant not a trace . Fluid stayed blue after repeated purging I even tested some with co2 from my beer tap and it Turned instantly yellow so the fluid is working . I’m thinking it’s most likely to be a bad intake gasket and not a cracked head or head gasket . Any opinions or recommendations would be welcomed.