What is the normal operating temperature for the RX-8 coolant system. The shop manual said the Thermostat initially opens at between 176 to 183 degree (F) and is fully open at 203. Now when the car is running and warmed up what is normal.

As we know the temp. gauge is worthless in the RX but I just received a ScanGaugeII and can now monitor my car's temp. After a short drive I noticed the temp level out at 164 (F) this is in 32 degree weather.

What bothers me is that this is leveling out before the thermostat is even suppose to be open.

 

probably a stuck thermostat

 

My Scan Gauge reading levels out at 82C to 84C (around 180F) with ambient around 0C

 

when cruising, my scangauge reads 180+/-1F, when in traffic it goes up to 190 to 20x when ambient is 70~90F

 

Just re-read your post.
How long was your drive?
It takes my car a while to get to 82C in cold weather

 

Now that the daytime temps are in the 50°s, my running temps are about 180°F.
When I stop, I see 203°F.
In the 100°+ Summer, its not unusual for me to see 225°F or higher (at which time I take severe countermeasures).

The thermostat "cracks" at 176°F. Its not supposed to be completely open until 203°F or so. Full fan temp is 215°F.
Nominal maximum operating temp is considered to be 220°F, which I think is too hot.

 

I dont have scangauge, or any computer program (I do have Scanlyser, but their program dont work on my Laptop .... and Last beta I heard was the one Swoope gave me ... *sigh)

but I do have Water temp gauge installed. when it first open, the temp will go about 82 Celsius. in Summer, I've seen About 100 Celsius.

 

Thanks guys, my first couple of drives were short so more observation is necessary but the temp did stop climbing. If the gauge is stuck or not working properly it would help explain two issues I have been having. Low fuel mileage and a long warm up time to get good heat in the car. Both of which I had told Mazda about several times with no resolution.

Again thanks.

 

If you think your thermostat is stuck open, replace it very soon. I had a stuck-open thermostat in my Accord. Didn't replace it right away. It finally failed closed, which led to a fairly tense limp home.

I never expected stuck-open to evolve into stuck-closed, but when I took the thing out and examined it, it became clear that this was a reasonable sequence. I was pretty lucky to not have damaged the engine.

Ken

 

i would only worry if it climbs over 212f and stays up there. i've seen 212 and then it drops slowly keeping the same freeway speeds as the thermo opens.

but then again, now that the weather is cooler, i see it even out around 180-190 on both oil and water.

 

180F sounds about right

 

212°F is actually still below Mazda's "nominal" rating of 220°F.

 

my oil temp usually sits *lower* than coolant temp. by around 20 Celsius.

it sync with coolant temp only if I push the car for a really long time, but the oil temp will go back down as soon as I go easy on the car.

 

OK. I've had several days to monitor now and the car runs pretty regularly at 178 degrees. Doesn't matter if it is city or highway. I guess my initial results were wishful thinking for trying to find a solution for the poor gas mileage. Coming to the realization that their is nothing wrong with my car, the MPG just plain and simply suck.

On a side note the Scan Gauge is pretty cool and simple to use. Provides a lot of the instrumntation Mazda should have included. Not an end all but for the money and portability pretty cool.

 

What are your ambient temperatures like? I presume they are close to freezing.
75°F+ seems to be the point where the coolant temp starts to rise more aggressively with changes in driving "style".

 

This is what you will see at the track after 20 mins of full on driving. Ambient was around 20deg C .
Pink line is the Stock fan setup slightly modified so that both fans come on full at 98 deg C
Blue line is fans on all the time .

 

That's nice an cool.
At those kinds of ambient temps, I would see about 10°F higher, but of course my motor would be under considerably more load.

 

+1
I would recommend this to any RX-8 owner.

 

We are in the running between 32 to 5 degrees over the last several days.

 

Normal coolant temps for me are 179-180F at ambient temps below 60F or so, at highway speeds.





More graphs from my little engine temps project can be found here, https://www.rx8club.com/series-i-tech-garage-22/engine-temps-115456/

 

recently my gauges started to read 185-205F during normal street traffic when its 50F outside when it use to stay around 170ish .... should i start to worry, car temp reaches those numbers fairly quickly now even though its cold outside.... i dont think i ever saw it go that high before when its cold out, oil temp doesnt seem to be affected... is something wrong?

 

Sounds OK, but watch the temps when it gets warm again.
170 is quite cold. 190 - 205 is what I see now that the temps are in the 60's around here.
When it gets back into the 90's, I'll see 220.

 

what scares me is that i dont hear my coolant alarm until heavy traffic and when its in the 90's outside , but i hear it now when its normal driving in mid 50-60temp outside..

 

hear a coolant alarm??? maybe you could explain that a bit.

does it have a warning light also.. if so what color?

this is new cutting edge info..

beers

 

haha oh no, i meant my prosport gauges have that feature, to do that annoying beep when your preset temps go past a certain point