Is there any concern with valley pipes or other coolant system components on a 2007 XK with 25,000 miles? Any other age related concerns rather than mileage maintenance?

 

You might want to consider replacing the plastic thermostat housing (which includes the thermostat as a unit). They do degrade with time and heat and if a piece of the housing gets caught in the thermostat, the result can be overheating. I just had this unit replaced on an 07 XK as a preventative measure.

 

Read this thread by Patrick Wong:
https://www.jaguarforums.com/forum/x...ervice-186165/
He replaced a lot of the coolant parts and provides a parts list.
The coolant reservoir (in particular the nipple leading out of the tank) is another susceptible component that ages poorly.