sometimes the radiator warning light comes on but when I check the water, it is ok.. any ideas on what causes this?

 

water pump, cavication, High temp -- your overheating.... could be you need a new thermostat

 

I'm having the same problem. My temp gauge never moves when the light comes on and it seems to only happen when it is pretty warm out. It usually only stays on for a few minutes and then goes off.

 

is it the one that looks like space invaders? the coolant light?
i believe there is a tsb for the coolant light. the sensors go bad and trigger the light intermittently. I just had my box replaced per tsb.

Or you may be low on coolant.

 

If you've check your coolant level and it is at the F mark when the engine is cold, then the low coolant level sensor which is built into the coolant reservoir is going bad.

It will get to the point where the red light will stay on constantly. Lots of threads on this problem ... search. Please don't follow the stupid advice of disconnecting the sensor or ignoring the red light ...... when your water pump fails like mine did, you'll be really sorry.

 

Space Invaders...LOL...never looked at it that way before but yes that one. My coolant level is fine. I searched a bit more and found this is a pretty common issue. I guess it's my sensor. I did see the "just unplug it" a few times, but I chose to ignore that bit of advice.

You say you had your box replaced per TSB. How does that work if you are out of warranty? I've always understood it to be:

Recall: mileage does not matter, dealer will fix problem for free

TSB: It is a known issue, dealer will fix problem for free as long as you are still covered under factory warranty.

Do I have this right?

 

Yep! The regular warranty 5yr/60 kmiles warranty, not the 8yr/100 kmiles warranty.

 

I have experimented with this light before. I used "Stop Overheat" which uses no coolant, distilled water and my light stayed on solid all the time. I went back to 50/50 last week and the light went away. If you are using plain water I think it doesn't register, maybe the coolant has a chemical that switches that light on when that chemical is not found or "closing" the loop?

 

And for a TSB outside of warranty? Any idea what the sensor cost to be fixed?

Mine does it seemingly when Ive been going relatively quickly for a few minutes

Thanks a million!

 

You maybe overlooking the issue.

I had the light appear only when on the highway and when the rpm's rose above 4000 rpms. I added about 5 oz of coolant and it completely solved the issue.

 

my light use to come on when I start my 8 from cold... I poured like 1/3 gallon of distilled water in the coolant tank and solved the issue. light never came back for over 4 months!

 

I was getting that for a while then I unplugged the connector. Problem solved.

 

ha yeah thats one way to solve it!

Mine just came back from a service which included a coolant change and the light came on first drive afterwards!

 

The sensor is built into the coolant reservoir, so the whole reservoir gets replaced. The reservoir can be purchased for $168 shipped. You'll pay more if the stealership fixes it.

 

https://www.rx8club.com/mazmart-88/brand-new-oem-coolant-tanks-173380/

great deal, got it in two days..

thanks mazmart..

beers

 

Good to know guys thanks

Im in the Uk but shipping shouldnt be to much.

How hard is it to fit?!

 

the dealership will perform a TSB for free any time it is needed, warranty or not. the warranty is different from a TSB. a TSB is a basically a known problem that is not significant (i.e., severe or widespread) enough to warrant a recall. Mazda will notify owners about recalls, but not TSBs.

 

they will preform a tsb for free if in the warranty period.. unless you are married to the service manager..

beers

 

it is pretty easy. but pull the battery and the upper battery box shield..

beers

 

I would still try adding more coolant. A lot of people think they have enough but they don't. YOu may also have a big air bubble or two in the system.

A local guy here had the light coming on and thought it was the sensor, turns out I added about a 1/3 of a gallon of coolant to his system and he was indeed low.

 

hey I'm having the same problem. I've checked the coolant level and it is full. the light only comes on during high revs or on the highway. if you take the car out of gear and let it idle it goes away almost immediately. I'm taking mine to Mazda in the next few days. I'm still under warranty so i don't think ill have to pay for anything. I'm using the Mazda recommended long life coolant and my car has 42k on the odo btw.

 

sensor in the coolant resivoir

 

That's not a radiator light, that's a White House. It lights up red because it means that the government have labeled you as a terrorist.

 

ahahhahahahahah

 

LOL!


Seriously though, can I put in any type of coolant, or does it have to be the MAZDA coolant stuff? My light went on and it's actually low. So, just add distilled water or just coolant, or both of them?