Temperature Gauge

QUOTE (mervyn2323 @ Jul 14 2010, 12:04 PM) index.php?act=findpost&pid=341579

Ever since we have had our i10 Style I have wondered why the temerature gauge only ever seems to show a maximum temperature of about 75-80 degrees. I have always understood that modern engines run at around 102 degrees with the radiator being pressurised to achieve this above boiling point temperature. Am I wrong in this assumption? If not this begs the question either the gauge or sensor is faulty or the thermostat is not closing properly, allowing the engine never to achieve it's correct working temperature. This may go some way to explaining the mpg figures being somewhat less than they probably could be! Anyone any advice to offer on this one?

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My guess is that your gauge is not displaying the actual temperature.

My previous car was an i10 Classic. I used to run an OBD scan tool and obtained loads of readings with it. I was always impressed by the fact that the coolant temperature, as read by the sensor, used to be exactly the same as that displayed on the gauge. The thermostat started opening at about 82 degrees C and was fully open at about 95 degrees C. That was the range the 1.2 litre engine operated in.

My current car is an i10 Comfort automatic. I also plug the scan tool into the ECU of this car, and obtain even more readings than before on my laptop. In contrast to before, the gauge does not appear to be calibrated on this one. The needle shows a good 10 degrees C less, i.e. about 72, when the sensor is reading 82. Hyundai, like other manufacturers, claim that the gauge is only an indicator, and is not necessarily spot on. Again, the 1.2 litre engine operates within the 82-95 degrees C range. It would have been neater to get the actual reading on the gauge, but it does not bother me. I just add 10!