It's leaking out of one of your pump bodies. They sonically weld the pumps together, and they split at the seam. You will find that it will only leak when the X5 is hot. This is when the plastic expands and lets the fluid slowly drip out. The seam is about level or close to the outlet of the pump. Smear some silicone around the pump housing at the weld ("when the pump is dry" of course) let it set, and off you go.