coolant

Hey my low coolant light keeps coming on and so today I took it to the shop. Because my warranty is still good on it and they kept it for like five hours. And then they came back to tell me that there is no leak it must have evaporated. I didn't know that coolant could evaporate. Besides that since the first time it started coming on I've added more coolant and I really haven't ever heard of it evaporating that fast since the last time I added some was in like august so thats only been around 2-3 months. Can anyone tell me if they've ever heard of coolant evaporating. Or do you think they just didn't know what they were doing and just said that figuring I'm a girl and won't know anybetter

The system is a closed system. Coolant doens't evaporate like that from a closed system. You have a leak somewhere. It may be small and just evaporates off a hot engine part. Or leak onto the road/driveway. Or it may leak into the oil. Or also into the combustion cylinder and then burn off.

A few checks you can do:
-Do you have any wet spots under the car when it sits for a while?
-Right after a hard drive, open the hood. Do you smell anything, particularly a sweet smell?
-Do you have white smoke coming out the tail pipe (not to be confused with water condensation)?
-Are your sparkplugs wet?
-Borrow a coolant system pressure checker from Autozone and test your system. It should be able to hold 15psi. If it drops more then a pound over 30 seconds, you have a leak somewhere.