It seems I have a coolant leak(only when the engine is running) which seems to be coming from a water line junction or distribution piece that looks maybe to be plastic. It is under the resevoir tank/ air cleaner inlet, down about a foot or so. It has a hose(maybe 2) coming into it from the radiator and 2 hoses leaving it going into the firewall. It has a device that looks like it might be some sort of vacuum switch with a wire or small hose leading off of it, right beside this junction. Is this associated with the heating system? What would this part be called so that I can order a new one? Apparently, it has a crack in it and leaks when under pressure.