Not to resurrect an old thread, but... after reading thousands of threads over the past 5 years, this would be the third one I have read about, if it'* the head gasket. The other 2 were after the fact. A mechanic just diagnosed it as the head gasket, and fixed it. It was at the same time as a UIM/LIM failure. Out of 10'* of thousands of problem threads, the head gasket is the very last thing to consider.
BTW, Another good way to check for an impending UIM/LIM failure is to check the spark plugs. The detonation with anti-freeze present will thoroughly clean one side of the sparkplug(*). You need some decently mileaged plugs to be sure (probably 10+K miles). It will clean a lean burn plug, and is really obvious on a rich burn plug. (I think I can find some photos if there is any interest.) I did pull the plugs and noticed some cleaning on a few of them, but at the time I didn't know to associate it with a leak.
My wife caught this situation well before I could be sure that the system was losing antifreeze due to the UIM/LIM on her '96. No chocolate milk oil or sweet smell from exhaust. A mechanic (who owns a '95 SE) and I both drove the car and it seemed OK. But she kept pestering that her car didn't "feel right".
Within the next month, she lost a half inch of antifreeze. I did the gaskets and found the upper just about ready to open the flood gates.
FWIW, maybe it will save somebody a hydrolock.
1995 SE ..Green and Rattle Can...234K mi...Bonnie (she'll outlive me)
1998 SSEI .. White ..119K mi...Evey
1996 SSE ..MajTeal..157K mi...4/12- Dealer trade full of Lucas Trans fix