The dealer is reporting that the top end of my radiator has cracked and leak where plastic and metal has bonded. The car is still safe to drive on but is probably slowing draining coolant. I like to get opinions if i should replace it with a new OEM radiator or aftermarket; racing one? Which option is best bang for the buck? I'm looking for reliability as well as performance. I do track my car 2-3 times a year. My car currently has 100K miles. Thanks,

 

Ebay aluminum radiator. I've been using mine for 2 ish years and it's never done me wrong. I think I payed around $150 for mine but it was a long time ago that I bought it and I'm not sure if that price is exactly right

 

Ebay radiator?? Sounds very risky. I did some search and it looks like the Ron Davis one has the greatest review but it's also close to $700 which is almost double the cost of a OEM one from Mazda.

Is the Ron Davis radiator really worth it? Or should I just get a decent radiator from $200-300.

Thanks,

 

 

I'm a fan of the CSF 3164 but the Koyo V2695 is probably functionally identical.

And don't drive it with a bad radiator. If it's leaking, it's not holding pressure. You could easily overheat and be on the hook for $3000 worth in engine.

 

I'm reading a few old post and someone mention that the S2 OEM radiators are much better than S1. Thoughts on getting this for my S1? Do all the other parts fit? Fan, etc?

 

Series 2

 

Series 1

 

Looks like BHR has the Koyo Rad for less than Racing Beat.

https://black-halo-racing.myshopify....mance-radiator

 

Series 2 has a thicker core and therefore is harder to fit. It's not plug and play.

 

 

I have been using the Koyo radiator for a few years with a ton of horsepower in the Florida heat with no problems, it has been good to me.

 

Thanks guys. I went ahead and bought the Kayo 2595 off Amazon. $261 total. I took it to the shop and they also recommend I get a new coolant tank just cause if breaks later, hes gonna charge me labor to replace it. In total, he said the cool tank is about $150 and new houses around $70 for top and bottom. Do you guys agree I should replace all just to be safe for another 100K miles?

 

I think the two Koyorad part numbers listed above by Sydo are the stock replacements they make...plastic end tanks and all. The all aluminum versions part numbers are:

Series 1: V2695
Series 2: HH062267

I believe both of the above parts are for MT only.

 

 

 

Ok, got it. Here's the dimensions for the all aluminum versions. Both have a little thicker cores than their respective stock replacements. I did replace the radiator in my S1 (used a Mishimoto, https://www.mishimoto.com/mazda-rx8-...-radiator.html). It has a 1.57 inch thick core vs. the 1 inch core on the stock rad. The only fitment issues I had were the mounting holes didn't quite line up with my car, so I had to slot the holes slightly. I don't recall any problems due to the extra .57 inch of core thickness. So perhaps the additional .1 inch a stock S2 radiator has won't be an issue. Though if the end tanks are much different in size, the brackets on the car my not fit.

 

If you do decide to get a new coolant tank you can get the OEM Mazda one on Amazon or ebay for around $100. Part number: N3H1-15-351G

 

Got it! Thanks. I picked it up for $110. The hoses were about the same price online so I will just have the shop buy that.

 

 

I bought a cheap $50 one on eBay a few months back and never had a problem. The only reason I went cheap was that I didn't know if the motor was good since I just purchased the car. I believe its common that the RX8 radiators go bad around that mile mark. I will eventually go for a aluminum radiator, but when I go REW swap :P