The only thing I'll add (pretty sure it has been mentioned too) is that one of the symptoms is an actual overheat condition that causes the sensor to freak out.

I mention this (it happened to me) for anyone planning to unplug it and play dumb.... You could be ignoring another, potentially serious, problem.

 

+1
rather dumb to unplug it and not have any way to monitor the temps.

 

Actually it isn't dumb to unplug it. There is a dash temp gauge , I suppose they put that there for a reason. Of course you could just leave it plugged in and pull out your hair on a regular basis or buy a new one every time the switch is bad and there are probably several threads and comments on how bad the switch is, but I don't think it is Dumb my any measure if you understand your car.

 

If the sensor is unplugged, it is not hard to check the coolant level at the same time you poke your head when you check the level of your oil. It's right in front of you

 

I relocated my bottle and haven't taken the time to extend the wires to it yet. Not difficult to check it, but I think it's much smarter to have it plugged in.
It would be nice to know if your losing your coolant while driving, that sensor is the only thing that can tell you that. Makes it difficult to check when the vehicle is in motion.

 

The factory coolant gauge is useless, it doesn't start moving until coolant temps reach 235-240F range. Coolant temps above 220F are death to the engine in a very quick manner as the factory coolant seals will fail beyond 220F so by the time your gauge starts moving to hot your engine may likely be toast already. Obviously you don't quite understand your car as well as you think.

And the switch goes bad, but it's not like it goes bad every 20,000 miles. I have 137,000 miles and only have replaced it once.

It's not hard, but neither is just fixing the problem properly.

 

that dash "temp gauge" is a dummy gauge. if it moves past halfway and you dont shut it down right away your fooked

 

Both are true statements, mine stopped working at around 140,000 miles. I just didn't want to replace it for $120 at that time because I started to have a leak, due to a broken engine coolant seal. So, I was in there quite frequently.

 

Thanks guys. Restored my faith in humanity.

Quick recap: Yes, it is dumb. Fix it just as soon as you can afford it and stop telling the newbies its okay to do anything but that.

Grace do you monitor temps beyond the idiot gauge? Hopefully you're starting to see my point blown water seals and all...

 

While i don't disagree with the fundamentals - to say your engine is toast if the guage starts moving is pretty extreme........

 

Factory coolant seals tend to fail above the 220F mark (at least that is what I have been told from the builders I have spoken with). The gauge doesn't move until 235F or so.

Sure, one could survive and overheating episode but if the gauge pegs you are probably in the 250F range and there is engine longevity damage being done there for sure. Stock coolant seals are just not meant to deal with that. Most engines will still run after an event like that but from what I have seen with guys who have done that, those engine tend not to last very long.

 

I measured 210F using the OE sensor (not gauge) and if it wasn't for my "faulty" fluid level light I likely would have overlooked it.

Jesse got to see it firsthand ... Twice I pulled over on the highway popped the hood, and scratched my head.

1 REmedy water pump, thermostat, hoses, and flush later I was back in business... And I did end up swapping out the bottle at the same time.

 

My own experience is that I,ve seen the guage move to about 3/4s and stay about there for several laps while tracking the car. My IC was too big and was blocking the rad. Coolant seals were fine afterward .

 

At 210F it still is on the cool side of the halfway mark

 

the coolant light is there to tell you if your low on coolant. its the sensor in the coolant tank that fails.

the temp gauge shouldnt move past just under the halfway point. if it does turn your car off. yhea a real gauge is recomended. you can also check coolant temp with a cobb

 

Its not a question of good or better or whatever. The OE water temp is also exposed as a open standard OBD2 PID...

 

Was that on a stock engine? How many engines ago was that?

 

Probably wouldn't hurt to get in contact with the MFG of the sensor for Mazda and ping them for information on the sensor that seems to be bad in so many rx8's. I unplugged mine. I watch my rx pretty close and at the end of the day it's my decision and as far as advise on this thread, I would caution that person against all the self appointed experts here, investigate your self man.

 

And what would be the purpose of contacting the manufacturer of the sensor?

 

Or you could just read the TSB, which explains the problem.

It's not unique to Mazda. A friend with a Corvette has the same issue.

Ken

 

your mother dropped you on your head as a baby?

 

It's a measure of your knowledge level about RX-8s. Anyone on here who listens to you is likely going to eventually get what they deserve.



.

 

"Knowledge is good"
Emil Faber

 

I'll take a guess @ sweatr, you just refilled your medical marijuana prescription ?
BC, too much knowledge is dangerous in some cases

 

so, my 2004 8 is having this check coolant light issue..... It started back last summer, I would really have to step on it (7k RPM) and hold it there for maybe 10minutes, the light would come on, I'm wondering if there's any relation to indicate water pump failure?? (no the coolant level isn't low, probably pinky low.)