Hi everyone. Not to beat a dead horse but....
I just had repairs done due to overheating. It went
over 240, smoke etc..
While driving yesterday I noticed temp on rapid
rise. Ie..in 1/2 mile went from ~80° to 140° . Am I
overreacting?? Is this ok to drive and watch to see
if it goes over 220?
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.
Your Cobalt needs to reach operating temperature within 9 minutes from a cold start up. If not the computer will set a trouble code and the check engine light will come on. So the rapid rise in temperature in the beginning is normal as long as the gauge settles in at around 195 degrees Fahrenheit. It's also not uncommon for the gauge to creep up to about the 220 degrees Fahrenheit mark if you're stuck in traffic in the summertime with the air conditioning on. If the gauge is rising past the 220 mark under those conditions or if you're driving and it goes beyond the 200 to 210 mark, something is going on that needs to be looked at! Hope that helps! Jim
Thank you so much. I feel much safer
You're welcome. Glad to help! Jim
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