I have an 09 cobalt LS with the 2.2 LAP. Last week I flushed the coolant out of the car and filled it with new dexcool. I rode the car for a couple hours and the temperature reading was always in the 180-190 range. When i rode it today, it kept reading 180 for about 30 minutes and then it rose up to 220 and the fan kicked on. then the temperature fell back down in the 180 range and then got back up.

I checked the hoses to see if the thermostat was working properly and it seems like it does. the lower hose is cold until i reach around 185-190 then it gets hot.

Is my radiator shot ? Is there something special I forgot to do when I changed the coolant ?

Can anyone help me please ?

 

You may have an air bubble in there. I think I've been dealing with the same thing.

 

The car will run cooler with the a/c on versus the a/c off. I know on my 07 LSJ, I was worried because I could idle all day with the a/c on and the temp never rose above 180. With the a/c off and the heater on in the winter, it got up into the 190's before the fan kicked on and then it dropped back down to 180. I have the tune on my car setup to run cooler than your car, though.

Just an idea... if your ac was off then I'd say normal.

If it's an air bubble, it would have worked itself out the first time you drove the car for a few miles. You'd know because the coolant level in the recovery tank would have dropped.

 

True about the a/c on or off. Also depends on if you were moving fast vs. slow. I have read that the fan doesn't even turn on until ~220°F unless the a/c is on. I wonder if the LNF is set up differently because I'm quite certain mine comes on way before that.

If you're not moving, or moving slowly, even if the coolant is flowing through the rad the temp isn't going to drop much until the fan kicks on. This could just be something you've never noticed before.

Mine, OTOH, went up to 223° at 70mph with a/c on. Even though it's hotter than blazes here, i'm pretty sure it didn't ever get THAT high before. I'm in the middle of making sure every bit of air is out but I'm not sold on that yet.

 

Keep an eye on the coolant level for sure. If 223 is the highest it goes before dropping down then i wouldn't worry about it. That's normal for a N/A Ecotec.

Just to be sure though, start the car and turn on the a/c, and then make sure the fan comes on.

 

I don't have an a/c in mine since I have an xfe so I can't try it with the a/c on. But I can tell that it heats up when i'm barely moving but if i get on the highway it is fine

 

Yup, totally normal then.

 

Maybe I never noticed it before. Thanks