So I took my 2008 xD to a mechanic because though the overflow was normal originally - the radiator was empty of all fluid, so the car was overheating. The mechanic said they couldn't find the problem after checking/adding fluids
to the appropriate level and driving it for 20 miles. There is no apparent leak. I picked it up and took it home. After my drive to work on Monday I checked the coolant in the radiator and found it was low again - though the overflow was a little over full.
I added a little to ensure I made it home OK and pulled some out of the overflow to get it to the full line. When I got home I opened the hood and found that the coolant was overflowing and bubbling out of the overflow and the radiator was low again.

Can someone help me out here?

Why is it that the coolant is going into the overflow and not back into the radiator? The overflow level is still high but the radiator is low on fluid again. There is no coolant in the oil and minus the overflowed coolant there is no drips anywhere else.
I wouldn't even know where to start with a new mechanic either since I have never had an issue like this.

Please help

 

You have a slow coolant leak. Take it to a better mechanic.

 

did u ever find a fix/ solution to this