I own a 1987 Non-Turbo RX-7 and me and a buddy just spent our Saturday installing a new Koyo Radiator along with a Corksport fan shroud. i was driving her around today and suddenly the "ADD COOLANT" light came on and the car was buzzing like crazy! I made it back home without any problems.

There's no smoke coming from under the hood and there doesn't seem to be any apparent leaks of any kind any where that i've been since i've been driving yesterday.

The coolant in my stock radiator was still pretty new, so i didn't drain it out of the block (couldn't exactly find the drain plug anyway, lol). We used half a bottle of concentrated coolant and a full bottle of water and that seemed to fill it up last night.

So can anyone tell me how much coolant and water is needed exactly for a
86-92 N/T FC3S Koyo Radiator? I'm trying to get her ready for Sevenstock XII. I appreciate it.

 

It's basically the same as the stock radiator, but that's not how you add coolant. You add it until the level is full, not in some set amount like an oil change. Use the bleeder screw and add coolant until it seeps out, then tighten the screw and top it off.