Jumped in the car yesterday to see a low coolant warning - looked at the expansion tank and the fluid was below the line. It’s the 4.2 SC.

To the best of my knowledge cars don’t burn through coolant so assume there is a leak somewhere so ideally looking for some friendly advice on where to start looking. All the videos I’ve found online are how to change the tank for a faulty sensor.
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I’ve topped the tank up, the warning has cleared and I’m sitting in her running at idle. It took less than 1L to fill the expansion tank back to the cold fill line.

Only visible thing I can see is the fluid in the tank moving and some minor air bubbles caught at the top. I don’t know if this is common because I’ve never paid attention to the coolant on this car before (my Volvo V70 D5 on the other hand… lol).

Any advice on where to start / or suggestions on what to search to find content other than expansion tank replacement would be appreciated

Sorry. Error on my part. Ignore.  Barrie.
2005 RRS 2.7TDV6 from 2017 -2024. Best car I ever had.
Current: 2018 Ford Ranger Wildtrak 3.2