Slowly losing coolant for months

Slow coolant loss for months. When starting the engine from cold, it shoots a good amount of either water or coolant onto the ground (it does not look pink). Then once going, it seems to be okay. There is a big puff of white smoke/steam upon start up, then it is okay once running.
What we have done already:
1. Changed to all new parts in cooling system: New radiator, hoses, hose clamps, water pump and thermostat, and heater hose connectors.
2. Checked the "color-change" test that changes the indicator fluid from blue to yellow when placed over the coolant reservoir - that test was negative.
3. Tested compression in all cylinders. All eight okay at 210 ft lbs.
4. Replaced the intake manifold gasket with a Fel-Pro, after sludge was seen in oil pan (also after using Sea Foam). The sludge was like black jello, which made us think of coolant in the oil.
5. Put water-based fluorescent dye in the coolant, then checked it daily with a "black light" in the garage after driving it. There were scattered fluorescent droplets in different places around the oil pan and transmission lines, but figure it was probably from the "start up" problem of shooting out coolant?
6. Did a "back pressure" test of cooling system. Okay

Could a hidden crack or blockage in the head cause the problem, and how would it be diagnosed?