Maybe I forgot to mention that there's no grille block to speak of. When the weather warmed-up a couple of months ago, the pie pans came out (same like the last 3 years).
I recently moved the front license plate out of the way, so we have near 100% air flow across the cooling surfaces.
Frank's earlier question has some merit. Nothing changed since last summer, and I'm having problems -- so another variable changed. Could the added water be masking something that isn't working properly -- like a stat, weak w-pump, crummy replacement rad? I went to NAPA so I got the "good stuff"
RH77