Engine Coolant Warning Light
 

when I started the car this morning, the engine coolant warning light came on. As soon as I put it into gear, it went off and stayed off. Will see what happens this arvo.

Only had a service just before the Nats, and there's no evidence of a leak, so it can't have run low.

Any ideas?

on the 04s and a think i recall that is what you have. the sensors do fail. a tsb was issued.. mine with 100k miles on it does it every now and then..

beers :beer:

search noob .

Had to say it cause swoope didn't - which really surprised me LOL

Sensor can fail sometimes. All is cool when the coolant level is checked.

nope,

i am nice now! :)

to much drama going on to start waves.. ;)

beers :beer:

I am sounding repetative about this recently so I am going to suggest you look at some of my recent posts in the .au forum. As much as its nice to get a new part I still think a lot of them aren't the sensor.

Cheers

Andrew

Thermostat? :eyetwitch

Yes, ok, I was a bit pushed for time, so didn't search.

Thanks guys. Didn't occur yesterday arvo or last night while running around (about 3 starts in total), so it seems like a random problem.

I'll see if it happens again and persists before doing anything about it.

Btw, love the noob comment...:lol:

nope...starts with "a" and we breath it.

Hi Dave
The problem is with your sensor. It has just happened to me, shortly before a service. It is intermittent, but it won't go away. Unfortunately, the cure is expensive. Mine was done at sevice. In the RX-8, the sensor is integrated with the header tank - cost $300.

:banghead: :banghead: :banghead:

Thanks Labby but if it's just the sensor and the coolant level is ok, I'm tempted to ignore it...at least for the time being...

Judging by Andrew's :banghead: 's, he tends to agree??? Must read his stuff on .au when I get five minutes...

Ok, just read Andrew's explanation of the suspected cause of the problem - i.e. cavitation, etc fixed by bleeding the system. See https://www.rx8club.com.au/forum/vie...g+light#p35987.

Well, how do you explain this? - I had the coolant system bled and re-filled only in September when I had the new whiz bang water pump fitted, designed to reduce cavitation!

So, why am I now having this problem? Either the sensor is faulty or there is something else going on...

I decided to get it fixed because we're going on a driving holiday in a few months, and I didn't want to have to deal with deciding whether it was a faulty sensor or the real deal somewhere way out woop.

Fair enough but buying a spare bottle of coolant would probably have been a lot cheaper for that trip! :)

<me sits back to await an explanation from Andrew and other gurus>

Yeah Taka reminded me that you had fitted yours so in this instance fair to say that its unlikely to be anything but the sensor.

In my instance (and I believe most who drive their car on the track) I replaced the bottle and it still happened. I learnt tobleed the system properly and hasn't happened since. I could even replicate the problem stationery if I had the patience.

Fair enough.

It hasn't happened again - started the car this morning, still nothing - so I'll wait to see how it pans out before doing anything about it...

I disconected my coolant (faulty) sensor ........takes about 30 seconds to do even the geeks could handle this mod :lol: :lol: , save yourself $ 300 and lots of headaches ..................and i have had absolutely no problems for 16 months .

I check my coolant levels every fill up with no problems .

Theres a pic somewhere showing how to disconect the sensor , i think it was MM who posted this .


Cheers
Michael

WTF ! you guys need a pic to show you how to pull a plug ? LOL

Some of them do .....................:banghead: :lol: :lol:

I got the coolant light signaling intermittently when the car was hot and had a weak concentration of coolant in the radiator. it was a concentration that my dealer recommended but not the manuals recommendation. I was reluctant to use the 3-4 bottles of mazda concentrate @ $33 a bottle the manual states. my dealer reckoned they would only use 1-2 bottles and the reduced concentration would be ok. the coolant check light went away when I refilled used a high concentration of ethylene glycol.

however your sensor was at a morning start? I think this happens when you have got the car hot on the previous drive and coolant runs down the return tube as it cools, splashing or triggering the sensor. hence it goes away.

I also think Andrew is correct as I think the trapped air bubbles "popping" out of the return tube splashes the sensor triggering it also. bleeding is better than $300 for a bottle and sensor you might not need.

Certainly my sensor was first noticed in highway traffic on a hot day, but it also played up when the motor was still relatively cool some minutes after starting. I'm a conservative person who works in a potentially dangerous environment, and you will understand it is totally against my nature and training to ignore any warning light on any piece of equipment. I'm also a bit obsessive/compulsive, and unexplained flashing lights drive me nuts.

I don't want to draw to long a bow on this, but perhaps you can see how accidents can happen in industry: "oh, that reactor warning light, it's been crook for weeks, so I disabled it, there's no chance the fuel rods will drop and it will go above critical mass......."

OK, let's say you're right, and the sensor problem is due to vapour locks, entrapped bubbles or whatever. At least I can go back to the Mazda dealer and say, it wasn't a faulty sensor, now fix it for good this time at your cost since the repairs are under warranty. The dealer claimed that they had run a diagnostic test on the sensor and had indeed determined that it was faulty.

I'm also not too sure whether reducing the concentration of coolant is a good idea. The coolant also contains an oxygen scavenger, which prevents rust from forming. The green dye is an indicator which tells you when all the scavenger has been consumed. Reduce the coolant concentration and you reduce the oxygen scavenging capacity. BTW, when the dealer replaced my tank, they also saved the coolant that they drained and put it back again

/\ - i see where you are coming from . .
I have also seen this discussed many times and experienced the issue myself .
If your tank is at the correct level it is the sensor - no getting around it .
Now if you are worried about your reactor reaching critical mass you will get it replaced quick smart . If you are like the rest of us who have had cars with header tanks for years and keep an eye on the level rather than rely on a warning light , you will just pull the plug .


All the stuff about air bubbles is a red hearing - the system is self priming/bleeding . If your light is coming on occasionally even when the level is right - sooner or later it will come on for good - FACT .

I have to say I never have the radiator light myself. The only one I thought it was "the yellow one". saying I need to refill the windscreen washer tank.

I use straight radiator fluid (may be 3-4 bottles with one bottle of water), but Jarl I get it at Ringwood Mazda for $15 a bottle!!!!! Yes I did go to Max Kirwan the other day for top one bottle and they charge $24. But $33????

Oh crap, why does everything on this frigging car need to be so f*#king hard??!