Coolant issue- 2010 Aveo LT

[navvet1]

Had to replace the thermostat/water outlet assembly last week, but have another problem that has me be-fuddled. The engine temp stays at normal, no check engine light, yet when the thermostat opens the coolant surge tank overflows. No sign of coolant in the oil. Ran the car with the cap off the tank to purge any air that may have been trapped out the system, still have the problem. Any suggestions? Thanks.

[avguy]

Replace the coolant tank cap.

[navvet1]

I take it you've had this issue?

[avguy]

I don't have a second gen Aveo, but you can find multiple hits on this being the solution to the problem you described. Search is your friend.