so i havnt driven the cobalt since the start of winter. i got in the car the other day because it was nice and the car drove fine no complants got in the car the other day after that and the coolant light was on so i opend the hood no coolant in overflow tank what the hell havnt flushed the coolant it has 38000 on it any ideas will greatly help

 

So your Question !
Where did it go ?
No puddle under the car then it had to go in or through the motor.
Check the oil to see if the dipstick has any froth on it or the coolant looks milky(head gasket)
Also is the oil level high on the dipstick(oil floats on the coolant)
Do you have white smoke coming out the tail pipe.(head gasket)
Other than that it would have to be leaking from a seal or hose and not getting to the ground ,take a good look.

 

not on ground white smoke all the time i live in mass p.s i am a mechanic just trying to see if anyone else had this problem

 

I had that happen. It would take a couple of days after I refilled. It was a small hole in the hose to the overflow tank, didn't leave any puddles since it was evaporating out the hole and not spewing out. Found it by accident when I heard a hissing sound.