Temperature gauge issue

I have a problem with the temp gauge in my ti. Previously the needle sat a little bit below the middle of the scale when enginge was at normal running temperature, but now it barely moves above the blue mark at the bottom. I have replaced the sensor with a new one (one wire flat bladed terminal) but this has not changed anything.



Using a DMM I have measured resistance over the senser to be around 160 ohms with running, hot engine. I have tried with a potentiometer wired in place of the sensor, and the gauge can move over the full scale. Around 60 ohms seem to put the needle in the usual normal-running position.

I have also measured the resistance between the hexagonal brass part of the sensor and the battery negative terminal and this reads 0.6 ohms so it doesn't seem to be a grounding issue.



The top rad hose gets hot so the coolant must be circulating.



Can it be an airlock that prevents the water from getting in contact with the sensor?



Or any other suggestions.



Thanks



/Per

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