urbanmonk

Hello Everyone,

I am new this forum or to RX8 world. I fell in love with it when i started looking for a used car as my first car after coming to US in 2015. Finally i thought i found one which is 2008 40th Anniversary Edition Automatic (41K miles single owner) bought from a private owner in WV. I recently bought it in Jan 2016. As soon as i secured it, went for a complete 150 point inspection + compression test at local mazda dealership. To my surprise, it failed the test though it was driving great (I made 400 mile ride from WV - PA - VA and some local driving). Luckily I blindly bought it because it was under warranty so i got new Re-Man engine replaced + out of my pocket Ignition Coils + Spark Plugs + Wires and Got all the maintenance related work for 30000 miles as previous didnt do any such. I wanted to makesure it was in good condition and service advisor told its all good.

And Feb was month where i was driving locally most of the time. Revving it when i could on empty roads for few secs. Everything was good and wanted to plan for long drive. Went for approx. 80 mile drive to MD and back to VA. While returning on free way, i revved it to 7k RPM for few secs hitting 110 mph and felt so nice and was planning for really long drive in the mind already (Amb Temp was around 65-70). As soon as i reach my home, thought of getting nice car wash and paste wax to pamper it as it nice weather. As i pulled up Flagship carwash, I could see fumes coming of the hood and guy there told me to check it out. The moment i switched of the engine, i see that temp guage crossing almost 80% and when i got out coolant was leaking. I felt it is very bad. Got it towed to dealership and found Radiator cracked and i will have to change it. Then i started pondering around google, RX8club interchangebly to understand cooling system for RX8 and which Radiator will be good.

And i could not find BHR Radiator for Automatics selling now a days. I am not sure whether to stick with OEM Radiator or find any other all aluminum aftermarket Radiator. As of now estimated charge is $1000 only OEM radiator + labor

Please advise on what to get for good cooling system so that i can do some hard driving on hot summer weathers coming forward. And also do you know workshops focusing on our models instead of going to dealership.

Thank you for help in advance.

Mod Edit:
OP...I moved this to it's own thread.

BigBadChris

iTrader: (4)

I would recommend a series 2 (2009-2011) automatic transmission radiator. Auto transmissions rely on a fluid coupling to transmit power between the flexplate and the torque converter. This fluid gets hot, and when it gets hot, it breaks down and does not function as well.

The auto transmission cars have a heat sink within the radiator to cool down this fluid.

Many aftermarket radiators lack this feature, the prevailing wisdom being that performance parts are targeted to manual transmission owners.

However, a series 2 radiator will help you. It is thicker than the series 1 unit, and the trans cooler will still function.

I purchased a large dual pass unit from RX8Performance.com, and then used a specially modified under tray to cool the auto transmission. An expensive solution, I admit. (Then I scrapped it all and converted to a manual. Because I'm a masochist)

urbanmonk

Thank you for replying.

I did a quick search for Series 2 (2011) OEM Rad AT, it costs $ 400+ including shipping.

RADIATOR for 2011 Mazda RX-8|N3R2-15-200B

I am in NOVA. Is this better than Series 1 Rad AT? in performance.

BigBadChris

iTrader: (4)

Yes, the series 2 unit is thicker, meaning the water spends more time in contact with the outside air. It is a pretty straightforward replacement. While you're doing this, you should check (or replace) your coolant. You should also check all of your radiator fans. Sometimes the blades snap off or the motors wear out

urbanmonk

Thank you.

This OEM Series replacement good for Hard driving/revving in hot summer long drives ~400-500 miles? and extended idling (in stop and go traffic), Here the traffic is horrible in rush hours, which takes around approx 1 hour reach home/work. If its good then i will straight away go for OEM Series Rad. And assuming it fits perfectly in my 2008 RX8

Orelse I was also thinking about after market Aluminum Rad.

I was doing lot of search but i could not find any Aluminum Radiators that fit AT. OEM Radiator itself costs $ 470 at dealer + $ 540 for labor costs. Thats when i thought of buying good aftermarket Aluminum Rad.

So now i have to buy an Aluminum Rad + Transmission cooler

From RX8Club, i have seen few which are currently available.

1) CSF Radiator - $ 255
2) Mishimoto - $ ~250
3) KoyoRad - $ 300 (Mozda motorsports) 355 - Redline
4) Mizi Radiator - $ 250
5) Ron Davis - $ 650 (custom made to order)

All these are Manual Trans

Trans Oil Coolers, I am not sure which one to select (Didnt find on RX8Club). There various brands from $ 28 to $ 100. Should i also get Water pump and Thermostat too?

Jmanie9515

Im in the exact same boat as you. I have an AT and I need a new radiator. I can go with the OEM again or I can spend the money on a nice Aluminum one. Except, they are all for manuals and I don't how to do this whole Trans Oil Cooler stuff. And would doing be just as good in performance as just getting an actual AT radiator. Please help