Head gaskets can fail in many ways, i've realized, since I've replaced two on B230F engines in recent year. I was loosing coolant in the 765 following an overheat incident (change those heater valves as preventive maintenance, this one failed at 160K). Coolant loss increased until BIG cloud of white smoke or steam billowed from exhaust. Oil also looked like chocolate milk at that point. had head shaved .010, changed head gasket and car's now running fine. Tough engines.

on the 945, i saw evidence of trickle, more like dry mineral deposit, at head gasket joint near No. 1 cylinder, exhaust side. so I spent the weekend doing that head to avoid a bigger problem.

in both cases, the head gasket near the coolant galley of No. 1 had deterioated, allowing coolant to leak into oil galley/combution chamber (765) and on the 945, from the coolant galley out the engine block, exhaust side. It pays to watch for leaks around the head gasket, or coolant loss, to stave off later trouble.
chris in vermont, 244, 945, 765 (sold and still runnin' fine)