I'm guessing that all at 8's have the same issues in this kind of heat and that most owners are blissfully unaware there is even a problem . So I'll stick with the 'mod it and to hell with Mazda' theme .
Just accept that maybe Mazda didn't get it right and to try and resolve it through them is a waste of your time and energy .

I look at it also as to the future of the RX-8. If my "little" issue can help Mazda to improve the cars for future buyers then what I am doing is worth it. I'm sorry I'm not going to stand here and say, "Oh Well." Sorry.
Issues with Mazda's vehicles should be addressed or they will just end up failing. They need to be resolved, not shoved to the side. And I don't want that to happen.
I love my Mazda RX-8. Even if it has problems, but i am not going to kick it to the curb because something is wrong with it. HELL NO!
Like I said if what I am bringing to Mazda's attention can better the car then I am all for it.
I will sacrifice for the betterment of the future Rotary owners.


I'll get down off my soap box now.
Thank you.

Fair enough if that's your reasoning .
I'm not that noble :) .

Hey Easy,

Just a long shot, but has anyone at Mazda checked the integrity of your wiring harness and ECU? Could you have a faulty sensor? Seems like they've tested or replaced nearly all of the mechanical things. How about electrical? Maybe it's YOU. Have you tried just driving someone else's 8 to see if it overheats when you're behind the wheel ;)

Nothing drastic just issues - Just need the two brains in the group. As usual I went farther than the current technology was ready for and am now suffering for my impatience. Overheating is just one of my problems that up until I did other mods I thought I had solved..........wrong.

Hopefully I can add something to this thread.

I'm from Houston and I experience this too. It's been in the 90's with HIGH humidity.

I don't have an accurate way of measuring temperatures, but in traffic jams my car goes crazy. I can mostly tell from the erratic idle and lack of power. Once the problem kicks in nothing seems to fix it.

When I autocross it doesn't seem to act up though.

My guess is light acceleration at low speeds for long periods of time just kills the car with heat.

Edit: one particular area of Houston I find myself in often is 30 minutes of gridlock. I mean barely getting enough speed to completely let off the clutch. Even when it was 70 degrees with high humidity the car was suffering and I could tell. I would like to see this problem fixed myself, after heat kills this one I wouldn't mind making sure the next doesn't die an early death!

Thanks HeavyMetal699, this is what I need from you people out there. I need information from anybody that is overheating. Please PM me with all the details you can think of. It will benefit everybody in the long run.

Ask every body you know with an RX-8 if they are having overheating issues. Let me know PLEASE!

Also, anyone chiming in should note if their temp gauge moves from its "normal" position of just slightly under the middle.
The OE gauge will begin to move up at 231°F.

My fans never came on until MM tuned it.

Well, that's because I turn them on 25° sooner!

I just came back from a car show so I was able to "Drive" the car .

Ambient Temp: 102
No Sun
max temp seen on AP :
While moving: 195
While stopped: 201
Avg speed: 44.3
Rpm & gear 4k to 6k in 2nd
Distance 12.7 Miles
Time in boost: Very little, no more than 100g/s

Coolant mix: 70/30 h2O/anti

I have the BHR AT Rad and I have seen very close temps that Easy posted.
Those temps were max 235 and min 201
1. During the day
2. In stop and go traffic NO AC

I know it's not an Apples to Apples comparison but it's the closest i can get.

^ Thanks Dave.

Im seeing the ridicuous temp as well. Now its kinda *usual* to see 225 degrees when its NOT even hot outside, like what 75-80 degrees ? about 50-80% Humidity.

The only way to keep it cooler is to go cruise at around 60 mph for at least 1 minute. It will slowly go down to around *around 203-199, but then if I stay at cruise, the temp for some reason will go back to around 210, depends on the throttle level I give it.

I have a question, for those who are *overheating*, Do you guys ALL have the MSP16 flash installed ?

Cuz it seems like it has something to do with this flash. Even when the FAN ON temp has been lowered.

Both Easy and 09Factor are AccessPORT, though Easy had the overheating before the AP as well.
Nycgaps - it sounds like you've lost a fan (or even both).

MM - Both of them still work tho -_- , I already checked them. fuse never burn out, and the fans did turn itself on at around 97 and 101 Celsius.

I dont know, Im kinda out of ideas -_-, let me just check them one more time today ... I might have missed something last time.

Could it be that the motors are slowly dying and not spinning *as fast* as its suppose to be ? Maybe I need to buy a voltmeter so I can test them? hmm

nycgps,

How many miles do you have logged on your 8? Is this the original motor? Hotter than normal operating temps (with everything else working properly) are symptomatic of a coolant seal that's starting to leak. Might want to do a pressure test on the motor to see if it's still within spec.

RCCAZ_1

If thats the case, that would be GAY.

my motor has 42K miles, and yes it is the original motor.

Lemme go Autozone and loan that coolant system pressure test tool back. or maybe I should go straight to Wayne and pay for the compression test.
-
Im going to recheck the fans first ... this is getting ugly -_-

partial throttle+ high rpms(6K) will absolutely run the temps up.
But yall's issue is much more than that. Mazda needs to step up. I think it is the a/c condenser placement---(it needs to be further away from the radiator) , the blockage behind the radiator and the angle the radiator is placed (10degree more to vertical can make a big difference)
I dont think mazmarts pump is going to make a big difference in low speed cooling---higher speeds it will for sure .
it is puzzling. i am boosted---regularly see 90-98F ambients. i am not in stop and go for a long period of time --maybe 10 minutes at the most---and i never see coolant temps over 200. usually between 180 and 190 with oil temps the same. If a 8 degree ambient increase makes this much difference then we are all riding the edge.
olddragger

Let's wait to see what other's say before you rent a tester from Autozone ;) I was just offering up my .02. Hotter than normal operating temps can be symptomatic of a failing coolant seal, but it could also be other things like an improperly operating thermostat.

nycgps, you know about my overheating woes and it turned out to be a jammed fan.. have you physically tried spinning both fan blades and seeing if they spin freely?

Luckily the only time I hit traffic jams nowadays is when I get off work or head to the gym.

I literally roll the windows down and put it on full heat in the floor board with it turned to outside air. It seems to help out alot.

It's a lot cooler (temperature wise)in Houston than Phoenix and we have swamp like humidity.

Oddly enough I've talked to several of the RX-8 guys in Houston and none of them experience the same problems. I'm not sure if its because they do not get stuck in grid lock traffic like I do or if they simply don't notice it.

I've never noticed my temperature gauge moving but I never really looked, I thought it was merely a dummy gauge.

Of course I do ~~~ lol !

Last week I took the battery box out and I spin the fan underneath with my hand, it spins ok with no hiccups.

Forgot to try the other fan tho ... maybe I should, I mean the fan does turn on but but but .... its still ...

I was just out for about an hour of driving and when Im back home ...

https://www.rx8club.com/attachment.p...1&d=1214068582

*sigh* ... Its 76 degrees outside ...

If I bring it to Wayne ... I wonder if they are willing to trouble shoot my issue cuz I have Koyo Radiator, Silicone hose installed ...

There is your problem right there.

I got so fed up with the thing overheating despite my Koyo and HUGE fans that I tore the whole thing out and went back to stock.
That lowered my running temps about 20° and made it much harder to overheat.

I've read a lot about that *Koyo* is actually worst than stock. -_-

but I never knew that the FAN ON temp can have such a HUGE impact on water temperature (Racing Beat's 87 Celsius vs Stock's 97 Celsius)

I have another solution on the way ... its time to say bye bye to Koyo :lol2: :lol2: :lol2: (Ebay da Old Koyo for 50 bux maybe, LOL!)

Hopefully I will get it by next week.

So the guage stays on one spot from about 180 through till 231 - wow that's a big range for "normal".
Makes me wonder if 231 is actually OK as a running temp ....

Interesting to note that at 239F Easy's guage has moved quite a bit - perhaps another 10 deg F and it would be in the red ....

are yall taking temps per your gauge or per factory sensor through the ob2?
if per gauge where is you sensor located?
OD

just talking about how the OEM guage stays in one spot (just below mid position) for a range af 50deg F

I live in Phoenix, as well, and the heat is ridiculous. However, with my BHR radiator, 90% distilled water, 2 bottles of surface tension reducer, and a splash of coolant, I still usually run under 200F during the high temps times.

Last week, it was easily 117F ambient, both fans ON (I have a switch to manually turn them on), A/C ON, cruising in the city at around 45-55mph, coolant temps were steady at 192F. Sitting at a stop light for 90 seconds and coolant temps spiked to 198-202 at the highest. Once moving temps dropped to 195-192.

These temps were monitored via my AccessPort handheld and my ProSport water temp gauge. When I got home, my AP was reading 196F as I parked the car in the garage. I hit the main top coolant hose with my infared temp gun and it read 192F. My ProSport was reading 190F, and the hose the sensor is in was reading 188-192 on my temp gun, so I know it's accurate.

I think with the AT's the combo of a trans cooler and the lack of the other oil cooler is what's hurting their operating temps. But like Erick has said, it's not his job to fix Mazda's mistake.

my sensor is located between the upper radiator hose.

so there is the answer - ditch the AT and get a 6MT ;)

I believe my next one will be a MT. But for now,,, :slap:

During my driving today around town, light traffic and outside temps around 112. Nothing above 50 mph and 4000 rpm shifting at 3000 rpm. I was seeing consistent temps of 205 to 234. Most of the time it was around 218 to 223.

My *8* is hatin' it too
 

Man, same crap down here in Tucson these past few days... if you guys remember my mods from my Flexalite fan controller DIY, I have the aforementioned fan controller coming on (both fans) at 185, vented hood, Mazdaspeed front bumper, and running 85% distilled H2O (the remainder is coolant with a bottle of RedLine WW). I also run no less than 10W30 (Penzoil Platimum Synthetic) here, I think it is nuts to run 5W20...even *if* I am getting 15-16 mpg.

The past few days where I have had to drive mid-day, I have had to use the A/C since I was toting around my dogs (otherwise I am windows down), and even with 91 octane gas, I was getting some detonation going up some long gradual hills.... holy crap, I have had detonation on I-10 going through Phoenix last year at 117, and me being an idiot had some 87 octane in the tank...I had to actually pull over and refill with 91 and octane booster to make it to California. But now here in town at normal speeds driving VERY conservatively I am getting some knocking (marbles in a blender) up some light grades. Damn. I let off immediately of course, and turn the AC off, but it sure is scary hearing that.

Normally my car (with my cooling mods) stays below 200 and everything is peachy. But with these extreme ambient temps, the car simply cannot compete, and the engine heat soaks so fast, there is no cooling things down once you've popped the heat cherry.

I can manually turn my fans on full blast at 'cold' start up, and this will help a tiny bit, but one stop light and temps get out of hand.... never mind stopping for a bite to eat, shutting the engine down and starting it back up within 5 min, is a real killer.

As a side note, I also have bypassed my heater core for the summer, so no coolant is running through it. I know I have reduced my coolant capacity by a small amount, but with my car computer right there, that damn heater core just cooks the inside of the dash for no reason...plus if you have that AC/Heater controls problem, you could get a blast of hot air unexpectedly! I am not going to fix the AC controls, so I have disconnected the air handler actuator, and also done this heater core bypass... in the winter I just reverse everything and unplug the AC fuse so I can get floor heat without AC on.

Anyways, sorry for the rant - bottom line, is that I agree with you Eric, this car simply is not suitable for super extreme hot climates such as where we live.
I know there are some cold climate issues too, but I think the hot issues are more critical since this motor (like Jeff said) is small, and thermodynamically inefficient, and creates A LOT of its own heat quickly as compared to most piston powered cars. I also feel this car has a crazy ability to hold heat inside the engine bay AND inside the cabin...I have never had a car that stayed so hot in the cabin for so long...I used to think it was the HVAC system pumping hot air into the cabin, but since I bypassed the heater core, it still is an oven in there no matter what!

Finally, why the F&$^#%K don't we have 93 octane in Arizona, where it is desperately needed???

-C

The cabin is heated by the exhaust system that runs through underneath. After I wrapped my midpipe , the drink holders are holders not warmers.

Did putting fans on the oil coolers ever get tried?

I know this doesn't help you at the moment Easy, but it may be a new reliability mod for AZ.

^^That wont work.

Ok. I am in suspense. Care to share why?

^^ It has been discussed b4 so ...

SEARCH !!! :lol:

Long story short, the proper way to mount the fans is behind the coolers. There isn't enough room to mount a fan which would have an impact without totally redesigning the bracket mounts.

Honestly, one thing I have considered is installing an RX7 oil cooler in line with the two stock coolers. It's been done and shown to work well.

Search done. The only link found on oil coolers and fans is: https://www.rx8club.com/series-i-trouble-shooting-95/oil-cooler-fan-86506/

Which I somehow missed despite regular lurking on this forum for 5 years.

Got a better thread?

I just don't understand why Mazda would not put two oil coolers on the AT. It seems to me that when you have a radiator that is not as big as the MT (due to trans cooler) that you would install another oil cooler.
I would love to hear the answer from from Mazda about this.

I can help them answer this

Thats because they totally underestimate the heat/Overestimate the cooler's abilitiy, Plus, Mazda wants to cut cost(cheap!)

While I might tend to agree with this assessment, it is interesting to note that Mazda had an RX-8 in Yuma in the Summer of 2002 for testing just this sort of scenario.
It is hard to believe that, experiencing what we have, that they would allow the car to go into production with a defect that could potentially yield such catastrophic results.
Of course, a certain amount of "loss" is acceptable to a big company like Ford/Mazda. But to sacrifice about $120 worth of additional production costs at the risk of several thousand dollars of warranty work seems short-sighted.

You could try running a totally non-h2o system.....

I believe TeamRx8 used Evans NPG with great success.
http://www.evanscooling.com/catalog/C_npg1.htm

It is pricey though, and you have to totally flush the OEM system of all water.
Edit: maybe your can convince mazda to buy it for you ;)

The Evans stuff doesn't make your car run cooler. It just transports heat better.
More than one well-known rotary expert has warned against it and I am not particularly sanguine about 240°F engine temps being acceptable, even if it is an operating norm for a particular coolant.

Alright then, lets troubleshoot; we don't think that airflow is the issue;

ATs have one oil cooler, Occam's says that its probably the oil coolers fault, assuming the trans coolers effect is negligible.

When the car is good and hot and exhibiting the symptoms wrap an ice pack around the oil cooler in/out lines. See if temps drop significantly, if they do install a second cooler. If they don't set up a remote system for the trans cooler, see if temps drop, if they don't then :donno:

The problem here is not so much that there is not something that will fix Easy's problem as the fact that Easy wants Mazda to fix it . Mazda are in a difficult situation because if they modify the stock system to fix the problem it is tantamount to admitting there is a deficiency and we all know what would happen if they did that .

BINGO!

Will Mazda void your warranty if you ask them to add another Mazda oil cooler? Mazmart sells them, I think. This is such a no brainer. How could they possibly object? Of course you shouldn't have to pay for it, but if you do, and it works, you will have at least taught them something. And we will eventually make them reimburse you.

I mean at this point its pretty obvious there is a problem with the OEM system in general I think we've all known this for a very long time especially on the AT's.

Now I would just like to know if its the Oil Cooler, the Trans cooler, something we're not considering, or a combination of both.

No, we don't know that.
We only know that taking the hood off didn't improve the situation.