Well, first things first. If your coolant was empty, were did it go? It's good for 7 years...it doesn't evaporate. Having worked at a dealership myself, I can follow with what Stanger88 is saying. I had guys that worked with me tell me ALL KINDS of b.s. stories, so I could imagine what they would say to someone they assume doesn't know as much as them. Some one just wanted to nickel and dime ya so they could get some extra $$$ from ya for coolant. Overflow bottles are pretty much just that. They can be empty, in fact every car I've ever built that was onna the first things to "get lost".