I've been getting this warning light for a long time now. (I have 46,800 miles on my XJ8). My coolant level is fine, not low, not high, just fine. But when I start the car this light comes on within just a few minutes of commencing driving. My Jag tech told me it's because the coolant is high and sloshes around and the sensors pick up some weird thing and then send a lot coolant light alarm. Anyone have any thoughts about this?