Coolant/Oil temp sensor calibration for AiM display

[cobar]

Is anyone using an AiM display that has been configured for the factory temperature sensors used for the coolant gauge and oil temperature?  (parts store link here)

Apparently it's a very common sensor used by a number of different car manufacturers and made by several sensor companies under the part number MD091056, but no one seems to publish any of the data. I've already checked with both US and UK AiM support, and a few Caterham specialists, without success.  When testing the resistance output at a few temperatures between freezing and boiling, it became clear this is not a linear output, so having the actual resistance curve is needed to ensure any accuracy for my oil temp readings.

Thanks,

John

[aerobod - near CYYC]

Hi John, although it seems difficult to find a resistance vs temp curve for the MD091056, one of the direct replacement equivalents is an MTE-Thomson 3119. MTE-Thompson show a stock curve for all their NTC temperature sensors that nominally has 2500 ohms resistance at 20C: https://mte-thomson.com/en/wp-content/uploads/2021/11/sensor-de-temperatura-2.jpg

This curve is close to the standard Bosch NTC curve (NTC thermistors with a similar nominal resistance will follow a logarithmic temp to resistance curve), especially from 20C to over 100C: https://www.bosch-motorsport.com/content/downloads/Raceparts/Resources/pdf/Data%20Sheet_70101387_Temperature_Sensor_NTC_M12.pdf

If the resistance of MD091056 is around 2500 ohms at 20C, I would use the Bosch curve, then confirm the AiM readings with an infrared thermometer measuring the sensor body temperature as close to it's mounting point as possible.

[cobar]

Thanks James, very helpful!  I've taken measurements at a few points that are pretty close to the Bosch curve.  I'll use that and monitor as you suggest.