107°c/105°c isn't too bad - though its crazy to see that on an 80°F day!
I needed to see daytime temps over 100°F before I went there.
With the second rad, I don't even make it there in 114° heat like we had today - even with the A/C on.
Generally, my oil is about 10° behind my water, as observed with a laser thermo.

 

I dont know man ~~~ I never thought that Koyo rad could be that "bad" in summer months. I installed it like last June but I never really experienced the *heat soak problem* until now ... makes me wonder is there something more than just the radiator problem. the differences for this year :

- I had different brand of coolant in there, Last year I had Prestone 50/50 then I added water myself to make it around 40/60 + water wetter, this year I use 100% Peak and watered it down, I've tried 50/50, 45/55, and 40/60. all doing the same thing. I also tried it with water wetter, same problem.
- Mazmart Water pump
- No more RB Flash. Got MSP16 about a month ago.

but last summer I didnt have Defi Gauges, I installed it after the summer so I might had this problem last year, its just that I didnt know about it. (cuz no gauge there to tell me, and its not hot enough for The stupid Mazda gauge to move)

if I keep the car on a cruise @ low speed like 60 mph in 6th gear. I can keep the water to around 93 & 80. but as soon as I stop or slow in traffic, it goes back up within like 1 minute.

it sucks man ... this sucks ...

 

Unfortunately I do not have any oil temp monitoring available with my present set up.
It's something I want to get in the near future though. Would be nice to see the difference in oil and coolant temps.

 

Its not that hard if an idiot lilke me can install it, Im sure anybody can install it within 1-2 hours.

and its not expensive either.

but your situation right now ... maybe later.

 

E,

You don't wanna know. My Gen 3 is an R1 and when I first bought her she was missing the passenger side cooler. Oil temps on hot summer days were consistently in the 225 to 240F range. I'm sure some of the brown areas inside my engine on teardown were the direct result of running with oil temps over spec.

Believe it or not, the Gen 3 RX-7s all came with single drivers side oil coolers except for the R1s that came with dual coolers. Hard for me to believe that Mazda would have dual coolers on the manual RX-8s, but omit them for automatics that place a much higher thermal load on the drivetrain. I'd love to have someone at R&D explain what they were thinking??

 

Just came back from checking my cooling fan,

I took my airbox and its undertray out.

I first spin the both fan with my hand, and I was like hmm the one under the airbox is not spinning as freely as the other one.

So I grab my K&N ver 2, strip the heat shield and the metal board, just connect the pipe and filter up to the throttle, idle @ 3.5K rpm so that water temp goes up and fan turns on. and ...

my eyes are telling me that, when both fans are spinning, the one under the battery spins with no shadow, but the fan under the airbox ... I can see the fan blade's motion blur. It does not seem like its spinning at the speed as it should.

Made appointment with Wayne Mazda on monday. See what they say.

 

what about some 3-pass radiators? here are some for FD's...

http://www.mazdatrix.com/b8.htm

 

i'm getting the urge to mod the car this weekend...

 

While driving yesterday with 09Factor, we were comparing temps. It was about 113-114 outside. I saw 232 a couple of times. We were not in any heavy traffic. Just normal Saturday afternoon stuff. I did notice that when the car hit 230 it would not cool off for a LONG time. No matter the speed , from 35 to 50. Just kinda stayed there for about five minutes. I did have the car idling for about five minutes at one point and it didn't get any warmer. After about three minutes it did drop about 5 degrees.

Anyway I haven't heard any thing from the Mazda dealer as to a specific time that the Mazda Engineers will arrive. And do?

Something else I noticed the other day. The panel under the engine is beginning to sag in the middle a little. It's starting to bow a bit. Another thing I noticed was the GAP under the radiator between the panel and the bottom of the radiator is quite large. It's about 2 inches between the panel and the radiator. This gap is pretty much a straight shot down the panel from the front lower air duct. Now if it's straight down the panel and the radiator is above it,,, hmmm. Seems to me I'm missing a lot of air flow capabilities.
So I was thinking about blocking that gap with some rigid foam. Or maybe making an angled piece of aluminum and mounting it to the lower panel and radiator and making a little spoiler to deflect more air upwards into the radiator. I kinda like the spoiler idea.

 

I'm in socal, it's warm here now. I just took my car out onto the freeway, temps were about 85-90 deg F

Was driving somewhat hard, staying mostly in 4th gear at freeway speeds
After a few minutes, I got the "low coolant level" light. Upshifted to 6th gear and slowed down and the light immediately turned off

Stopped my car in a shady spot and lifted the hood, coolant level in the resevoir was good and the engine bay didn't seem excessively hot

Is this a problem caused by the OE pump not being able to flow enough? Something else? How much should I be concerned?

Thanks!

 

Seems to be a common problem in these cars. The coolant level sensor sucks ***** and randomly lights up.

 

https://www.rx8club.com/series-i-trouble-shooting-95/coolant-light-dash-118947/page3/

 

Most helpful forum ever, thanks guys!

 

Erick,

There is one aspect of my RX8 which I've noticed many others are not doing. As you know, I removed the plastic grill and replaced it with mesh wire. I also gutted the VFAD and all the other stuff in the front grill area. The plastic grill is almost completly closed for airflow except for the very bottom.

While some of the air runs into the impact areas on the bumper, it does appear to open the front nose to a larger amount of airflow. Today I was driving with 100 degrees outside with no A/C on and at highway cruise of 75 to 80 mph I was seeing temps around 175 degrees water and 180ish oil. It only went up to around 200 degrees in slower city traffic.

I can also confirm that I've seen better temps by mixing in a little bit of anti-freeze into my coolant system. It's made at least 5 degrees of difference in cooling. Needless to say I was very surprised.

You can easily purchase powder coated wire mesh to install on the grill. It might be worth a try if it doesn't go against the theme/style of your RX8.

 

So for those of you that have experimented with different water to coolant ratios, what has worked best?

In another thread MM posted in reply to me that 40/60 had worked best for him. I assume that is 40% coolant, 60% water, but I couldn't tell for sure. Figured it would be more appropriate to discuss here.

I think I saw where olddragger said 30% coolant, 70% water worked best for him.

Any other thoughts? Since I live in the midwest, I think I will try the 40% coolant, 60% water. The stock 55% coolant mix was getting in the 230s for me on the track, with oil temps in the 240s. So I want to try to improve that by changing the coolant mix and adding my second oil cooler. If that doesn't work it might be time for radiator shopping. Being an AT guy, my shopping options is a very short list of one option, I believe...

 

I've been using 70% distilled water and 30% antifreeze. Also a bottle of Waterwetter.

On another note I just found out today that the Mazda engineers will be out in the beginning of next week. Weather looks to be in the 110+ degree range for there visit.
Wish them luck in figuring something out.

 

I use 85% distilled, 15% Prestone concentrate and a bottle of water wetter...
and my custom fan controller set to start coming on at 185 F.
works great; nothing is a better 'courier' of heat than pure water, but the drawback is that even though heat can be carried away efficiently, it also can hold, and heat up quicker if you don't have airflow over the radiator. There are other electro-chemical issues too, but in AZ cooling is my priority.

 

I expect a full report on that Friday or you will be sleeping under the stars on a park bench A solution would be nice also - that would get you dinner.

 

I'll have a report for you Phil. What it'll say is another thing. As far as a solution, I have a solution. BHR radiator and Mazmart waterpump. And an additional engine oil cooler. I have a feeling that would solve my problems.
But I would have to do that. I want Mazda to do something.

 

if anyone is using the rb cold air scoop --one thing to know--the shape of this scoop among other things, causes a swirl affect at the top of the radiator. That is not good.
Just keep that in mind.
olddragger

 

Well today is the day that I take the car in to let Mazda figure out what's going on.
Wish me luck.

 

Post some pictures or this never happened !!!!!!

Good luck, my pawn ...

 

I hope they have an answer - this is getting ridiculous.

 

Maybe thanks to Easy's efforts, we'll get a recall that will put a second oil cooler on all the ATs...

Yeah, and monkeys might fly out of my butt.

 

Good luck today