Engine radiator Koyo or OEM BMW

I have a Koyo radiator on my 2019 and am really impressed with it. You get a thicker core and all aluminum construction so you don't have to deal with the metal/plastic interface of the OEM one that can crack/leak over time.

I've been using an OEM style Koyo Radiator for the last 10 years on a clutch fan. Multiple track days and never any overheating issues.

I opted for a stock replacement Koyo with the plastic end tanks again. It'll get you buy for another 10-15 years and 100k miles.

I have a 2008 e90 335xi FBO with 197k miles and I am still on my original BMW radiator. If the stock original BMW stamped one works well... why experiment?

Bought a Koyo rad for my na. Fit like a glove and it's hand built "from what I've heard"

My koyo was bought secondhand, has done many track days and 40k street miles over 5 years, and I even accidentally tried to jack up the car with it. It's still going fine.

installed a koyo radiator. Very beautiful fitment

I did a Koyorad in mine and it was pretty straightforward. No complaints whatsoever

I bought a Koyo OEM replacement (not the bigger Race version). Absolutely perfect fitment.

Roughly 12 months ago, I upgraded the radiator on my 2000 Series 8 (~65,000km/40,000mi) to a Koyo R1443N 48mm N-Flow. The coolant seals blew because the radiator's design allowed air to accumulate, creating hot-spots and leading to seal failure. My water temps never exceeded 90C. After a rebuild, a valve was installed on the radiator elbow, making it quicker to bleed the system, and water temps are now around 77C, about 10C cooler than before. The Koyo radiator's design prevented proper bleeding of the coolant system, causing seal failure.