Temperature Gauge Segments Actual Temperature

[Reatta45]

I did this on my ?91 Reatta coupe.

Using the diagnostic function in the ECM along with a very accurate digital contact temp probe and an IR temp gun. I set out to see if I could come up with any thing.

I removed the engine thermostat to even out the temp readings that I was getting externally.

I also found that my engine sensor was quite accurate.

The first segment I did not record.

The 2nd segment comes on at 115 degrees F.

The 3rd segment comes on at 131 degrees F.

The 4th segment comes on at 147 degrees F.

The 5th segment comes on at 167 degrees F.

The 6th segment comes on at 184 degrees F. (This is the 12 o?clock position).

The 7th segment comes on at 212 degrees F.

The 8th segment comes on at 217 degrees F.

The 9th segment comes on at 223 degrees F.

The 10th segment comes on at 230 degrees F. (This is as high as I wanted to go)

I did not go to the next segment; I removed my air flow restriction and allowed things to cool down.

The cool down, (segment turn off), lagged about 1 degree cooler than the turn on temp. for any given segment.

I repeated this complete cycle 3 times with no variation.

It appears that this display is NOT linear, the temperature changes after the 12 o?clock position light up the next segment with a much smaller change in heat. This is good as this is when it should be catching your attention? I do not know at what temperature the red segments light or at what temperature the ?HOT? indicator lights? Hope I never see them. KennyV.

[Guest F14CRAZY]

When we drove the '90 coupe home, the radiator lost coolant like twice (don't ask if you haven't read the story...) and the gauge got full except for the last segment and didn't get the "hot" warning.

In my '89 I once got it around 230f but still no hot warning. Supposedly, Reattas will shut down if they do get hot enough (electronically, that is. They eventually will shut down...)