Sweaty Baby

I have a very important question that I need answered and I’m calling on all you moms out there since I’m new at this. See that little guy down there?  He is uber hot natured at his ripe old age of almost 7 months. We aren’t even in the heat of the summer and the poor little guy has almost over heated several times just from riding in his carseat. I turn the AC on full blast and that still doesn’t seem to help much. Do any of you have any advice for this? Any breathable carseats you can recommend? Does this carseat cooler thing or something like it work? HALP!