tgmilazzo

As I was getting halfway into changing the AOS on my 03 C4S I noticed lots of coolant pooled up on top of the block under the drivers intake manifold near what I think is a knock sensor. I cleaned up one puddle then took a picture.

The reason for the AOS replacement was a broken nipple for the coolant line that runs off the passenger side of the AOS. Previous owner had it bypassed. Also found corroded wire coming of the starter and a broken wires to the changeover valve under there which should be the reason for a bad changeover valve code I'm getting. I guess my question is where do you think the coolant up there came from? Could it be from when the nipple broke and was bypassed but no one ever cleaned up under there? Would it evaporate over time ( I have no idea how long ago this bypass happened)? I still have a slow persistent coolant leak, I'm doing the water pump, thermostat, and lots of new coolant hoses as part of this job so who knows. Just curious if I should now be looking for a different source of the leak while I have this all apart. Also any other tips on getting the AOS bolt toward the rear of the car back in? Took forever to get it out...