After I drive my 2006 XK8 for 20 - 30 minutes, I get the red light and a message ENGINE COOLANT LOW. The temp gauge never indicates any thermal distress. After I shut it off and it cools down, I take the cap off the coolant res and lo and behold -- plenty of coolant! Could this be just another bad electrical connection, ir is there some deeper mystery?

 

It is remotely possible that the connection to the sending unit is faulty. It's more likely to be the parts in the plastic tank. Replacing the tank is easy DIY and about $50 for the tank which comes with a new sending unit and cap.

I covered the DIY in my thread here

 

If you have a problem with the Expansion Tank, a replacement (P/N MJD4400AB) comes complete with Fluid level Sensor and Pressure Cap. If it is only a low coolant sensing issue, the Fluid level Sensor (P/N LNA5740AB) is available separately.

Graham

 

I would add that there has been a rash of these tanks lately, reputedly in new condition, that come with a faulty float sensor. Be prepared to bench-test the new part when you get it so you don't have to do the job twice. And also double check the return policy, including return shipping, or buy locally. I and others have found that the best mess-free procedure for anything related to this tank is to use a turkey baster-type tool to cleanly empty out whatever is needed, instead of flushing the entire system.

Best of luck, keep us posted.

 

Thanks, all, for your help with this, and for letting me have access to your experience. The dealer down in Marin County has been real good about getting parts for me, and I think I will just go ahead and order the entire tank/float/sensor assembly from them