Mazda - Low coolant temp light

[440Magnum]

Originally Posted By: Miller88
Most cars have a blue low temperature light and a red overheating light now. No more (fauke) gauges!


I've never seen ANY vehicle with a "fake" temp gauge. Not saying they aren't out there, but I've never seen one. Some have idiot lights, but none that I would buy.

I've never owned a car without a real, live, working temp gauge since that '62 Oldsmobile. The only fake gauge I've owned is oil pressure in the 08 Ram and that's why it has a mechanical gauge mounted on the dash. Even the Cheap Cherokees have fairly well calibrated, oil pressure gauges and coolant temp gauges. The older cars have oil idiot lights and temp gauges. The SRT has a coolant temp gauge, a bunch of warning lights, and everything else you want to know (including oil pressure and temp digital readouts with bar graphs below) in the EVIC display.

I'm not a big fan of idiot lights. A full complement of gauges and a "check gauges!" light and chime when any one goes out of range is the best solution of all, IMO.

 

[SwampSurvivor]

Originally Posted By: 440Magnum
Originally Posted By: Miller88
Most cars have a blue low temperature light and a red overheating light now. No more (fauke) gauges!


I've never seen ANY vehicle with a "fake" temp gauge. Not saying they aren't out there, but I've never seen one. Some have idiot lights, but none that I would buy.

I've never owned a car without a real, live, working temp gauge since that '62 Oldsmobile. The only fake gauge I've owned is oil pressure in the 08 Ram and that's why it has a mechanical gauge mounted on the dash. Even the Cheap Cherokees have fairly well calibrated, oil pressure gauges and coolant temp gauges. The older cars have oil idiot lights and temp gauges. The SRT has a coolant temp gauge, a bunch of warning lights, and everything else you want to know (including oil pressure and temp digital readouts with bar graphs below) in the EVIC display.

I'm not a big fan of idiot lights. A full complement of gauges and a "check gauges!" light and chime when any one goes out of range is the best solution of all, IMO.



Most recent Fords have fake temperature gauges. They stared the fake oil pressure gauge too.

Their fuel gauges leave a lot to be dired as well ... they are not even remotely accurate ... But that is a different topic.

 

[Minou]

The blue light goes off in my 6 at 55C (131F) according to my Scangauge.

And yes, it has a red overheating light that will flash if severe.

Overall, I don't miss the gauge that much.

 

[Hokiefyd]

Originally Posted By: 440Magnum
I've never seen ANY vehicle with a "fake" temp gauge. Not saying they aren't out there, but I've never seen one. Some have idiot lights, but none that I would buy.


Most temperature gauges are programmed to correlate with engine temperature, but do not track exactly with engine temperature. Especially in those vehicles with electric fans. Coolant temperature in vehicles with electric fans can vary by as much as 40 deg F, and a true temperature gauge would be fluctuating all the time. Most customers get dismayed by that, so the gauges are heavily "damped" (or simply programmed) to show a slow-but-continuous rise to what is deemed "operating temperature", and then stay there unless the temperature rises beyond that operational range.

For example, my '97 Cadillac had a temperature needle gauge, but also would read the coolant temperature in the driver's information center. The needle was straight up for coolant temperatures of about 188 deg F through about 232 deg F.

This may be what was meant by "fake temperature gauge".

 

[SwampSurvivor]

Originally Posted By: Hokiefyd
Originally Posted By: 440Magnum
I've never seen ANY vehicle with a "fake" temp gauge. Not saying they aren't out there, but I've never seen one. Some have idiot lights, but none that I would buy.


Most temperature gauges are programmed to correlate with engine temperature, but do not track exactly with engine temperature. Especially in those vehicles with electric fans. Coolant temperature in vehicles with electric fans can vary by as much as 40 deg F, and a true temperature gauge would be fluctuating all the time. Most customers get dismayed by that, so the gauges are heavily "damped" (or simply programmed) to show a slow-but-continuous rise to what is deemed "operating temperature", and then stay there unless the temperature rises beyond that operational range.

For example, my '97 Cadillac had a temperature needle gauge, but also would read the coolant temperature in the driver's information center. The needle was straight up for coolant temperatures of about 188 deg F through about 232 deg F.

This may be what was meant by "fake temperature gauge".


Exactly!

My Cherokee has a "real" temperature gauge.

 

[KrisZ]

To be honest, I think the blinking red or solid red indicators for overheating are probably a better idea than the gauge.
I think most people are more likley to notice and react to (read pull over) a blinking or solid red light than a temp gauge that is raising or is pegged in the red zone.

 

[NateDN10]

Originally Posted By: Hokiefyd
Most temperature gauges are programmed to correlate with engine temperature, but do not track exactly with engine temperature. Especially in those vehicles with electric fans. Coolant temperature in vehicles with electric fans can vary by as much as 40 deg F, and a true temperature gauge would be fluctuating all the time. Most customers get dismayed by that, so the gauges are heavily "damped" (or simply programmed) to show a slow-but-continuous rise to what is deemed "operating temperature", and then stay there unless the temperature rises beyond that operational range.

For example, my '97 Cadillac had a temperature needle gauge, but also would read the coolant temperature in the driver's information center. The needle was straight up for coolant temperatures of about 188 deg F through about 232 deg F.

This may be what was meant by "fake temperature gauge".

So what of the digital temperature gauge in the Cobalts? Under most conditions, it doesn't vary by more than 5 degrees (but it *does* vary). And like I said, under situations with low airflow (like a traffic jam after driving at speed for an hour), the temperature will climb to over 210 degrees. And likewise, in the dead of winter, the temperature will decrease if idling for an extended period.

My point is that if a regular temperature gauge shows the range of, say, 70 to 270 degrees Fahrenheit, there doesn't need to be excessive damping because the normal +/- 15 degree fluctuation won't move the gauge enough to be worrisome anyway.

 

[Thermo1223]

This is what I remember when playing with the Accessport in or Forester regarding the cold light.

I think it shut off around 130F, but it could vary based on outside temp because technically going from 0F - 180F is worse on the engine than 80F - 180F.

 

[440Magnum]

Originally Posted By: Hokiefyd
Originally Posted By: 440Magnum
I've never seen ANY vehicle with a "fake" temp gauge. Not saying they aren't out there, but I've never seen one. Some have idiot lights, but none that I would buy.


Most temperature gauges are programmed to correlate with engine temperature, but do not track exactly with engine temperature. Especially in those vehicles with electric fans. Coolant temperature in vehicles with electric fans can vary by as much as 40 deg F, and a true temperature gauge would be fluctuating all the time. Most customers get dismayed by that, so the gauges are heavily "damped" (or simply programmed) to show a slow-but-continuous rise to what is deemed "operating temperature", and then stay there unless the temperature rises beyond that operational range.

For example, my '97 Cadillac had a temperature needle gauge, but also would read the coolant temperature in the driver's information center. The needle was straight up for coolant temperatures of about 188 deg F through about 232 deg F.

This may be what was meant by "fake temperature gauge".


That's certainly better than my interpretation: one that basically has 3 needle positions: "cold," "normal," and "too late." The ones in the Challenger, Ram, PT Cruiser, both 60s Mopars, and both Jeeps are pretty linear in a broad span around normal operating temp. Only the Challenger has actual numerical temp markings, but the others move the same way, and yes you can see them move in response to the electric fan (Challenger, Polara, and PT- the Jeeps, Coronet, and Ram have at least one engine-driven fan and so are more stable).

Linearity and a gauge that DOES move is very important to me, because you can see a problem happening. I've actually overheated the PT once.

The gauge worked very well, very linearly, and warned me that it was having a problem a long time before the "check gauges" chime went off. I saw the problem with two gauge bars left, so I could slow down, turn off the air, stabilize the engine temp, and get another 50 miles to the nearest town. Turned out the thermostat wasn't opening any further than it did in my wife's usual short commute, and when we made a long highway run that wasn't enough flow by the time midday heat arrived and we were already well out of town.

 

[440Magnum]

Originally Posted By: KrisZ
To be honest, I think the blinking red or solid red indicators for overheating are probably a better idea than the gauge.
I think most people are more likley to notice and react to (read pull over) a blinking or solid red light than a temp gauge that is raising or is pegged in the red zone.


Thats why I said that I prefer gauges WITH a "check gauges" light and audible chime.

I still have the habit of a periodic gauge scan from all those years of driving older cars with nothing but gauges except for oil pressure. Its better to see something going on early, IMO, and non-fake gauges offer that option.

 

[Hokiefyd]

Originally Posted By: NateDN10
So what of the digital temperature gauge in the Cobalts? Under most conditions, it doesn't vary by more than 5 degrees (but it *does* vary). And like I said, under situations with low airflow (like a traffic jam after driving at speed for an hour), the temperature will climb to over 210 degrees. And likewise, in the dead of winter, the temperature will decrease if idling for an extended period.

My point is that if a regular temperature gauge shows the range of, say, 70 to 270 degrees Fahrenheit, there doesn't need to be excessive damping because the normal +/- 15 degree fluctuation won't move the gauge enough to be worrisome anyway.


If your coolant temperature doesn't vary by more than about 5 deg F, that's extremely stable, and very uncommon, especially for a vehicle with an electric fan. Your engine probably has a 195 deg F thermostat, and GM typically doesn't set the electric fans to come on until about 225-230 deg F, excepting air conditioning operation of course. So you're probably looking at an easy 20 deg F temperature swing under even moderate conditions. The gauge in our Cadillac didn't begin to move until the temperature got to about 130 deg F. I imagine your Cobalt is likely similar. I think the range of most gauges, if one were to plot temperatures, would be about 130-200 for the "cold half", then 200-270 for the "hot half".

And it certainly depends on how many degrees your needle swings. Our Cadillac's needle had a full 180 degree swing from cold to hot, so small variations would certainly have been noticed. If the gauge is small and only swings through 45 degrees of travel, for instance, then similar variations would be much harder to detect.

 

[NateDN10]

As an update, I got a ScanGauge II for Christmas, so I now know that the blue light turns off when the coolant hits 130*F, while the thermostat keeps the coolant around 180*F when fully warmed up.

 

[nepadriver]

Originally Posted By: NateDN10
Our new-to-us Mazda5 has a blue indicator light in the instrument cluster. To quote the owner's manual,
Quote:
The light illuminates continuously when the engine coolant temperature is low and turns off after the engine has reached normal operating temperature.

Does anybody know what that actually means? I would define "normal operating temperature" as the temperature at which the thermostat starts to open and therefore the coolant temperature stops increasing.

However, the light goes off much sooner in a drive than the coolant temperature would have stopped increasing on either of our other two cars.


I plugged an ODB II Bluetooth code reader into my 13 Mazda 3, connects to smartphone running Torque app. Mazda works similar to other Japanese cars, start up, light blue = cooant temp under 140 F, after 140F turns off. Stablizing in sub freezing temps on the highway just under 180F. I think on our Subie it happened around 120F (blue light turned off).

Mazda doesn't seem to warm beyond that point without driving it, I had it idle one cold morning and I shoveled snow, for a good 5-8 minutes, light still blue. Drive it 1-2 miles it shuts off (Torque confirms its over 140F). If you read the OM, thesystem will throttle up within 30 seconds of turning the engine over, tries to get engine up to temp...

Interesting note, on a cold day (under 20F) after it gets past 140F, and I'm driving home, mostly down a steep hill, requiring no throttle, for a few miles, it has turned back on indicating the engine coolant cooled below 140F.

I believe the DI engine is pressuring gasoline, that is below freezing temp-wise, into the engine keeping it cooler, longer, than a standard NA engine. Just my guess.