Engine radiator Koyo or Nissens

I replaced mine with a Nissens and it’s been working great for over a year. The way the drain plug felt when I installed it was a bit concerning though.

Pretty sure oem is mahle but nissens are good for sure

Nissens rads are very good tbh, better than OEM,

the Koyo certainly looks much better. You won't notice any difference in cooling between the two.

I'd go with Koyo for price and ease of install. My reservoir hose nipple broke on my OEM radiator (OEM has plastic tanks) so I went with all aluminum for durability. My RX-8 also only drives on race tracks, so the extra cooling is nice.

I'd replace it with a fully aluminum one just because of that pesky plastic nipple that's prone to breaking. Koyo makes a good one.

I’ve had really good luck with Koyo radiators in the past as a really good replacement. The couple all aluminum radiators I’ve had, I really wasn’t impressed with the quality of construction.

I went Koyo. For me even with a stock engine its worth it not to have a plastic seam to worry about.

I imagine, if done right it could be stronger than original. But unless it's a really good radiator, I'd replace it with one of those $70 nissens.

The problem I'm running in to is that the upper hose connection is positioned differently on the Koyo N-Flow/dual pass(RH020539N) and it's really close to the Q45 throttle body and attached TPS. I've already cut off the unused socket on the TPS which gives me more room but still not a ton to work with.