I'm a new RX7 owner but I'm not new to the HEAT OF THE SUMMER. I have had problems with over heating on a Ford 150 after I removed the stock clutch fan and went to Electric. I found a product called 40 Below that you add to the radiator mix. Since using this product I have never had any over heating problems in any of my cars. I also have a 89 SUPRA running 14 lbs. of boost that used to get hot in the summer Texas Heat but no longer. There are other products on the market called water weter, Roal Purple makes something also. I can not tell you how they work. If you can not find it in any of the speed shops let me know and I'll find you the place to get it.

Brian