I think I have found the source for an odd "quagulation" of thick yellow-green goo.
I have a 98 Legacy auto 2.2L engine and just under the upper return hose to the radiator, there has been an odd accumulation of sticky goo under where the hose and return pipe join. I'd been noticing it for several months and had wiped it all away (much effort) and tonight I noticed it was back. Just about 1/32 inch thick and a very small pool sitting on the engine block and a little dripped on the timing belt housing. Anyway I was poking around and again removing the "goo" when I noticed that the capture screw and bands was not tightened over the hose and return pipe! It was not tightened at all. Could this hose have been operating almost perfectly (no noticeable steam from under the closed hood) for up to a year and just been dripping a little coolant and drying on the hot engine block? I never noticed anything dripping under the car.
I wouldn't imagine that pressure-cooker type steam builds up in the cooling system, but I would have thought that a loose connection under hot engine use would have leaked more fluid. Anyway I tightened up the capture screw and the band is tightened now.
As for fluid loss, I have added about a quart of straight coolant to the overflow container over the past 6 months or so. Tonight I added about another quart.
So, was the semi-dry goo I found, dried coolant? Anything else I should watch for?
Djay