His theory is that the water will evaperate quicker, where the coolant won't, but in my IMO, he should have used a sealent with all the studs that go into the water on the block (some holes are blind) I never put an engine together with studs that i don't use sealent on all the studs and with alum heads i use sealent if i use bolts.
JMO
Zip.