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,,,

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.

 

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 !!!

 

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.