Yes, that sensor goes directly into coolant.


IF you replace the sensor with the engine COLD you can do that with-out losing coolant. start by removing the radiator cap, squeeze the upper hose, & re-install the cap with the upper hose still collapsed(still squeezing it).
That will create a vacuum allowing you to replace that sensor.

OF course draining & refilling with fresh anti-freeze is also a good thing to do with winter coming on...every 2-3 years for fresh anti-freeze is still a good idea.

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