Check Coolant Level

I get this message on my dashboard all the time. I have a e39 540. I check the coolant and it is totally full. Is this a sensor thing?

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Yup - the sensor pushes up into the bottom of the expansion tank. There is a magnet attached to the bottom of the "pop-up" indicator, which signals when you're low on coolant. Sometimes the magnet comes loose, and stays at the bottom of the tank. That, of course, keeps the reed switch in the sensor closed, and tells the body computer you're low on coolant. The sensor can be replaced as a separate part - you don't have to replace the whole expansion tank. You do pretty much have to remove the tank to get at the thing, however. You may be able to finesse it out if you're agile ;-) You unplug the wire connector, and give the whole thing about a 1/4 turn counter-clockwise, then the sensor drops straight down and out of the tank. Put the new one in, re-connect the wire harness, and you're good to go.
Tim/
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George Johnston wrote:

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-Fred W

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Fred W wrote:

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-Fred W

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