Twice recently I've got the BONG and a 'Check Coolant Message'.
The first time I added about 150 mL coolant. (It was last topped up about 6 months ago so I'm not seeing any sort of leak.)
The second time, today, I checked it again and the coolant is right at the top of 'full'.
The car is running nicely and the temperature is staying right where it should.
I'm using the orange coolant stuff and premixed it 1:1 with water before adding, so it shouldn't be an issue. I don't know when the coolant was last flushed, but it has the proper orange colour and looks nice and clean.
Any help would be appreciated.
PS The message goes away. It's not continual. The car is a 2008 non-Super Jag 4.4 petrol with a little over 100K miles.

I suggest to drain the coolant tank and fill it with new mix and see if that helps. Otherwise your sensor (plugged into the bottom of the tank) may be faulty a bit. I replaced mine (don't forget to remove the tiny rubber cap on the tip of the probe before installation) and the message went away (with the correct mix). The sensor wasn't very expensive I remember. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

^^ Had the same recently on my 2006 80k 4.4 AJV8 - with a check message twice over a couple of months.
Investigation by my specialist revealed a slight split in the bottom of the radiator.
All fixed after new radiator fitted.
Just for info, I'd only had to put a small quatity of top up coolant in it - there was no deluge.
I've seen a couple of these cars for sale stating they had a new radiator fitted - maybe it's time for a new one -

 Where do you go after one of these . . . ?

I did a howto on just replacing the sensor (which is easy and doesn't require a drain down) but this doesn't always work, and sometimes the only way is to replace the coolant tank. CTC was going to cut an old tank open to see how the sensor works, as if you can replace it without draining down it is not in the coolant so there may be a sight glass or similar in the coolant tank. .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

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