I need some help here before I start digging. Ths is the only link I could find that addresses this in a near similar car. I have a 2002 super 8 which is the xj8 vanden plas with a supercharger 103k miles.
I drove across the state yesterday and the radiator fluid light came on (low fluid). The temp gauge stayed low so I drove to an auto zone. They didn't carry the orange fluid so I added water to the top off. It did not seem low but the light went off and I had no further problems. 300 miles back and forth same day.
Today, I drove about 8 miles and when I turned off the car I noticed the high speed fan kept running. this never does this. The temp gauge was in the middle where it always is. I opened the hood and let it cool down. I added some orange fluid to the top off even though it was pretty full. I then drove about 3 miles to Staple, then the grocer store. The fan ran again at the grocery store for about 5 minutes. I drove home (5 minutes) and the fan kicked on when I parked it and the gauge red light was on and moving to the top. I shut it down and the high speed fan ran for 5 plus minutes. I checked the gauge and turned it back on. Gauge was normal, fan kicked on again when I was turning it off (2 minutes) and ran for about 2 minutes. The fluid does not look great and it def. is not orange. Today I drove it about 5 miles and the fans kicked on and the temp started to rise. I turned off AC, kicked on Heater and the temp started to drop down to normal pretty quickly. Thermostat? If so, how do I change it out. I can't find anything online to show me how to find it or change it out.


2002 Jaguar Super 8 -103000 miles Florida car

 

Look at this other thread on XJ SC 98-03 coolant outlet assembly (shows how to remove/install thermostat) See post# 8:

https://www.jaguarforums.com/forum/x...er-pipe-58829/

Jim Lombardi