When I drive my 2002 XKR with 86,000 miles for more than 20 miles, I get a Coolant Level Low warning. I've checked the coolant reservoir & it doesn't appear low at all. Any idea on is causing this? Where is the sensor for this test? Perhaps I need to replace it. Thanks. Don

 

Could be a failing float or sensor in the coolant expansion tank. Is this vehicle still running its original tank? Highly unusual for one to last that long without leaking....

 

Thank you for your reply. Think I'll get a new reservoir & see it that fixes the problem.

 

My wife’s ‘99 had the same condition and I must have spent 12 months trying to trace the problem. No obvious leaks, no water on the garage floor. I replaced the water pump because I didn’t want the plastic impeller factory version anyway. No change. I replaced the coolant hoses, but it was time anyway. Checked the heater core. Replaced the overflow tank cap. Eventually just left the car running on the lift for 10 minutes. No leaks, but I did notice a few small microscopic bubbles around the new overflow tank cap. Interesting. No traceable leak because while driving it evaporated. I replaced the overflow tank completely and the leak has never reappeared. The float sending unit on the bottom Of the tank fell off when I removed the tank so I suspect it could have contributed as well to the leak. . Hope this helps.

 

I glued my sensor in after repeated warnings on a french campsite with rough tracks.