Coolant light, sensor behaviour advice needed
 

So the light has been coming on with highway rides, after about 10 min at 130km/h. I don't take the highway very often so made nothing over it since the engine temperature was not rising either. Recently, cold weather at around 0 degrees overnight results in the light coming on for about 5 minutes or less as it warms up initially, then i don't see it again.

Checked the manual, looked in the reservoire tank, there appears to be fluid, sure, but its difficult to determine exactly how much. Just dug up my flashlight waiting for the car to cool down to have a look at the level again, don't know how much luck i'll have.

Got about 45k on my 2009 r3

Cause of the positioning of the radiator, ive been explained that adding coolant is not too easy, if i need to add any at all. I don't knew enough to suspect a sensor misfunction.

My car had a bad sensor which was causing an intermittent low coolant light. It was fixed under this TSB:
http://parts.arlingtonmazda.com/docu...40-10-2375.pdf

What, the coolant sensor goes bad? Get the F out of here. You learn something new everyday :rolleyes:

I just unplugged my sensor. I know I have enough coolant in there and my temps have been fine, the light was very annoying.

OP Yes, you have (like me) some of the early 09 S2's which do not have the latest and so called greatest coolant bottle Sensor Float installed....mine is the same as yours...I ignore it and am waiting for the float to sink completely (constant dash red rad light on).

Will the new Sensor Float now used eventually sink?...well jury is still out..so far no 2010 or 2011's (or updated) have had this issue....yet.

You might want to rethink that. No one needs a warning light to know whether they have enough coolant before starting a drive. It's when you suddenly loose coolant while driving that the warning is critical.

Ask me how I know.

Well it is either have it on 90% of the time or have it off 100% of the time. Having it on all the time helps nothing, it wont get brighter or flash if I suddenly lose coolant. I wish I could have the light working but I spent weeks toying with my coolant level thinking I could get the light to go off and never could so I gave that idea up.

Got the Mazmart coolant tank and it cleared the light right up. My coolant light was on pretty much any time the car was in gear.

Count as warranty work, then?

If you are still under the bumper 2 bumper warranty then yes, otherwise the TSB is just to let the techs/dealer know about the problem and how to fix it.

I think there would be very few if any RX-8's (Series II) which would still qualify for B2B Warranty on the Coolant Bottle Float, seeing Mazda is only recognising those RX-8's produced before May 19, 2009, those RX-8's made after this date already has the latest and updated Coolant Bottle Sensor Float.

Basically meaning MY 2010 and MY 2011, it will be interesting to see if these Senor Floats sink and if those who already replaced CB's, if the reliability is holding up OK??.

I have an 09 R3. Haven't checked if my VIN is below the # in the TSB. But isn't the B2B a 4-year 50k warranty?

I would doubt many 09s are still under that. Considering whether an intermittent warning light is worth the labor to fix it.

Mazda US B2B is 36 months or 36,000 miles.

My 2009 RX8 has the same issue with the coolant light.

So can I get a change of the tank for free at my mazda dealer?

lolo:rofl::rofl::rofl: