Hi,

whilst driving in city traffic my water temp gauge idles in the middle (as it should?) but on longer motorway trips its idling in the lower quart of the scale.
Therefor its pretty cold out there, as the heating doesnt blow hot air out anymore...
Is this a serious problem? What could this be?
Thanks in advance, TAG1000

btw: It's a 1999 4.0 XJ8 Sovereign.

 

sounds like the thermostate is stuck open .. or ect sensor fault.. both will give you less mpg

 

Is there a way to check if the Thermostat is still alright? Or do I have to change it anyway? Thanks

 

Thermostats on these cars go out more than Paris Hilton in Hollywood. It's a good idea to replace the thermostats every two years as preventative maintenance. Not that expensive and an easy job.

 

I aid just change it .. You will see when you pop it out it will be open and stay open..