On my way home today from work (25 outside) check engine light popped on. Scrolles through the info and p0128 popped up for not reaching temp. Coolant only reached 145 in my 45 minute drive home. Heat seemed start blowing warm fairly quick (guess thats not hard when its 25 out)

Im almost sure its a thermostat thats stuck open. Anyone have this happen to them? And does anyone know of any decent thermostats for this car? Not trying to get some crappy one from advanced auto.

06 ss/sc

 

Ive had this happen on my cobalt and my sky. You can get the ACDelco thermostat from some parts stores. I believe autozone carries Mahle ones too. Youre definitely right about it being the thermostat, might as well fill it up with fresh dexcool at the proper mixture while youre in there too.