A look behind air pump with the electrical connection unplugged






Been getting the low coolant warning and could not find any signs of leak until today.
C300 with 120k miles.
Dried coolant is above thermostat housing and behing air pump buried under the two small yellow lines that run behind the mount for the air pump.
I hope it’s just coolant that is somehow traveling up from failed water pump seal and not a crack in the aluminum housing at the thermostat.
Any help is appreciated