Okay, so I keep getting a random coolant light on the dash every now and then. It gets more frequent everyday. I have checked the coolant and everything is fine? Does anyone know where this sensor is? I want to check the sensor before I go all the way to the dealer. Thanks.

 

i believe if you add just a touch of coolant the light will go away, even though it looks ok.

 

Cool, thanks.

 

The sensor is on the bottom of the overflow bottle.
Mine started freaking out a couple of thousand miles ago. For a while, over-filling the reservoir would cause the light to go out, but now it is on most of the time.
I am running a bigger radiator (that should make no difference to the level sensor) and a higher pressure cap (same), but the intermittent light started before I added either. It started on motor #1 and is the same on motor #3.
It definitely isn't a level issue or air in the system - the light comes on while the car is just sitting there with a normal amount of coolant in the bottle.

A friend here in town that is a tech at Berge Mazda says he has started to get '8s in with the same problem at similar mileage.

 

Yeah, mine seems to only come on when I am hauling *** (which is most of the time). I freakin' hate dash lights so I hope this is not a issue that cannot be resolved. I wonder if the dealer will give me **** since it probably will not come on when they have it.

 

i had the same problem so i took it in to mazda they said it is normal because the engine sucks in so much coolant when you get on it that it trips the sensor as having low coolant.mine would come on for about two minutes then shutoff.thats what i was told sounds pretty legit to me cuz the coolant is not low or anything.
Funny i just started a new thread asking the same question then i took Mugato's advice and here i am.....

 

There are two things wrong in that explination.

1) The engine does not "suck in" coolant. It recirculates it. You can't "suck in" more coolant that you are already recirculating in a full system. Depending on driving conditions and temp, the coolant may be deposited and then drawn back into the system in small amounts from the overflow tank but no where near the level that would trip the sensor. Something is wrong with the car. My guess would be the sensor itself.

2) If this were true, then every RX-8 would have that issue. I've owned two, neither had this issue, nor has any other one I've driven when I "got on it".

 

Its the sensor. A bunch of folks here in the southwest are having that problem.
The entire overflow bottle gets replaced because the sensor is integral.
I just unplugged mine. It doesn't tell me anything useful.

 

one member had the same prob...n turn out to be the sensor was dirty..no more prob after cleaning the sensor

 

How would one go about cleaning this sensor as it is molded into the bottom of the tank?

 

My sensor light is permanently on, how does one disconnect it as MM has said its as useless as **** on a bull

 

Dealer just changed mine. Due to random coolant light activation.

 

Did Karl have the bottle in stock? What was the internal cost?

 

Could just be sediment . If you took out the tank then fill it 1/2 full with water & shake the bejesus out of it ............ - might be worth a crack anyway .

 

Tried that. No dice.
I dried it out and sprayed it with contact cleaner too.
The float isn't sticking, its an internal failure in the switch.

 

No, they had to order the new bottle, not sure on the price.
I got the new overflow tank because coolant had leaked into the sendor and would short it out, causing the light to come on.

 

I had this issue once... Really scared me too... It was after some "spirited" driving, while I was waiting at a red light. I got the coolant light for 30 seconds and then it went off.

I'm mostly worried that I didn't put in a good mixture of water/coolant, but I haven't seen the coolant light in weeks, so no worries so far...

 

I was talking to another 8 owner and he's having this same issue.
Under load (Higher rpm's) for an extended period of time, the light would come on and then go back off, after normal cruising.

 

I'm seeing the same thing - spirited driving of say 7k rpm for over 30 seconds or so equals coolant light, drop the rpm's and the light goes away. A double check of the coolant level shows that is not the cause of the problem.

The temperature gauge shows no increase in engine temp so it does sound like a misread of a sensor as opposed to an actual issue.

 

These things are dropping like flies around here.
Coolant overflow bottle replacements are starting to catch up to engine replacements for the #1 warranty issue at my local dealer.

 

But I hope it's not starting a trend. Get a new overflow bottle,get a new engine.

 

I think they're up to Revision H now. the whole coolant overflow bottle.

Lucky I dont have this problem.

 

The cost of the coolant overflow bottle is around $400.00 aus so simple disconnecting the sensor solves the problem and ..........costs nada

Thanks MM for the pics but i do preffer your avatars

Ben

 

Any time.
Just make sure that if you unplug the sensor that you stay on top of the level in the bottle and aware of your engine temps.
Don't let an unknown boil-over claim your motor.

 

I also had the light, but it was at cold startup in the morning. Stayed on for about 30 sec. then I haven't seen it again.

Anybody know if there is a TSB being worked on? Sounds like this is an issue. Certainly one that I will get fixed before the warranty runs out!