2007 cobalt

Normal operating temp is ~190-200 degrees. There is a thermostatically controlled valve that stops coolant from circulating through the radiator until the engine reaches 190 degrees. Temp should rise quickly and then slow way down at about 180-195. Over 200 degrees you are overheating.

Overheating after repairs is often air trapped in the cooling system. it can be challenging to get the air out but it has to be done. Might require a shop with the proper equipment to do it. Money well spent.

If there is air trapped in the system, you should be able to take care of that without a shop.With the engine cold and not running, remove the radiator cap and top it off if needed. Leave the cap off and start the engine. Allow it to reach operating temp ~190 degrees and add coolant if the level in the radiator drops. Never open the cap on a hot or running engine, the system is under pressure and near boiling point. The other option is to allow the vehicle to do the work for you. No need to touch the radiator cap this way. Make sure the expansion tank (some people call it a reservoir but it is not a true reservoir) is full of coolant (to the line) then start the engine, let it get to operating temp above 195 then turn it off and allow it to cool completely. Repeat several times checking occasionally to see if the level in the expansion tank has dropped and refill as needed.

Thank you so much. I feel much safer