I've started getting the Check Engine Light on and off. It's code P0128 (Coolant Temp Below Thermostat Regulating Temperature) I figure replacing the thermostat would likely solve this, yes? Anything else it could likely be? How much should I be looking to pay for a new thermostat and any other things I'd need for it on a 2001 330xi?
Almost always it's the thermostat. The part is $50-$75, depending upon where you buy it; takes 1-2 hours so it's a $200-$300 job for a mechanic. If you DIY, don't forget to get the G-05 coolant before you start. Also consider replacing belt and other cooling system parts if they haven't been replaced recently. I think there's a little hassle removing the fan, so check into that before starting.
