Edmonton JoeKer

Ok, I have read in some of the threads already that the RX-8 has an inherent problem with the temperature sensor and giving false readings. Anyone know how long a new one will last? I am assuming that they will have the same problem and you just keep replacing the darn sensor.

Also, and yes I am sure this will be considered a "dumb question" but I'll ask anyway.. I'm new:

Is there a risk of running the engine too cold with the rotary engine? I'm wondering if a guy is concerned about actually overheating, can you run another row in the rad? What else can be done to ensure it doesn't actually overheat?

BigCajun

iTrader: (1)

I'm not sure what you mean. The temperature gauge does not give an accurate reading, changing the sensor won't help.
You can get the Torque app for Android, or more involved mods to get accurate coolant temps.
I believe there are aftermarket radiators that may help.
Sundays are kinda slow here, try again tomorrow.
Good luck.

kevinande

The temp guage is not inaccurate, the vehicles computer is simply programmed to stop moving at approx 160F and begin moving again around 220F or 230F, somewhere in that range. At any rate when the guage moves again toward the hotter position, your pretty much screwed. Your best bet is to install an aftermarket guage to monitor the coolant temperature.

From everything I have read it is not a good idea to run the renesis at any temperature lower than 160F. I have gotten the impression that the sweet spot is about 200F. I am assuming that running it any lower than 160F does not allow the metals to expand properly, which is why your not supposed to thrash it around until it reaches operating temperature. The car is even smart enough to not let you go above certain RPM's while it's still cold. If you radiator, hoses, stat coolant bottle and coolant are in good order, overheating should not really be a huge concern. I do choose to run an aftermarket guage set to keep an eye on things though.

RIWWP

iTrader: (2)

The coolant sensor with the problem is the coolant level sensor. As long as you don't run out of coolant, there is no direct connection between the coolant level sensor malfunction and overheating.

You don't want to run the RX-8 lower than 170F, since you will get CELs and a huge gas mileage penalty (the ECU is looking for it to get above 170 to start running closed loop and stop dumping in fuel, and if you don't get there fast enough, it will pop a CEL). The sweet spot IS 200F in terms of operation, however since you can damage a coolant seal at about 220F, which is UNDER the temperature the coolant temp gauge will start moving again, 200F only gives you 20F of head room. I personally prefer running it at around 172F-175F, to give myself more like 45F head room.

However, you can't run an engine lower than the thermostat temp. Adding another radiator helps you shed heat down to your thermostat temp. If that other radiator is bypassing the thermostat, then yeah, it will over-cool your engine in quite a few circumstances. If it's operating on a thermostat, then no, it can't overcool your engine, just help you stay at the thermostat temp.

But, you can't just add another radiator without proper planning. Fitment is one thing, cooling routing is another. It would be better to just get the BHR radiator, which is more effective than the stock radiator, and just drops in place of the stock one.