Quote Originally Posted by Forest Gump View Post
It probably wouldn't hurt to bypass the radiator cooler and go with a large aftermarket one.
Agree here. While not a 3S I saw fluid temps drop drastically on my Grand Prix when I installed a Hayden 1403 cooler. The cooler is actually ran in series with the factory cooler too, so if I ran it stand alone I could see even lower temps. It is pretty big, but not even close to the largest they offer. I was barely able to make it work without cutting or modifying anything.

My temps before the cooler would sometimes approach 230* on hot days on certain roads. It hardly ever goes above 200* anymore.