I had coolant loss for about 10k miles before I could find the leak. Although the leak was from the UIM, I replaced the LIM at the same time. It too was worn thin in places and would have been the next to go (if not already)
My coolant was leaking where through where the bolts were located. In the below pic - under the wires that go over the UIM.
....it would pool around the bolt and then evaporate, making it difficult to detect...untill it started to leak worse.
My leak was on the lefthand side, however I could see remnents of coolant on the right.