Recently my 2011 XJL kept spiking on the temperature gauge and the air conditioning would shut down. Not a good thing when its 100 outside.
Well after having the car about 4 days one of the junior technicians suggested taking the cowling cover off over the radiator. When they did what they discovered was a bunch of dirt and busted up leaves had accumulated in the core radiator area thus plugging any opportunity to allow the thing to breath. Cleaned out the radiator with hose and much mud just ran out but now the car runs great. Suggest that if you ever end up driving where a lot of dust is blowing that you check your radiator out.

 

Pleased to know you got it sorted. I vacuum out a couple of times a year in that area of the car.