2000 XJ8 running cold

[timskipper]

I've just bought a 2000 XJ8 3.2 whcih I believe may have some kind of cooling issue. I know the temp gauge is software operated which might mask the issue, but it only really gets up to the middle if you sit a let it idle for long enough. Driving last night in low temps and speed and it was reading about 25% from cold.

The heater doesn't blow especially hot either.

Could this just be a faulty thermostat?

[a8hex]

timskipper said:

Could this just be a faulty thermostat?

Sounds very likely. When the thermostat on my X300 failed the car would run really cold. I have a block heater so I could pre-heat the engine but within a couple of minutes it would be cold again.

[timskipper]

Replaced the thermo - problem solved. Well, that problem anyway!

Neither rad fans appear to be working, I left it idling for a long time. A laser thermometer recorded the rad at 98 degrees and the two main rad hoses at 75 degrees so I didn't want to leave it much longer in case it caused an issue.

[t400ble]

When should they cut in I wonder?
The system is presurised so wont boil at the standard 100 deg c

[t400ble]

t400ble said:

When should they cut in I wonder?
The system is presurised so wont boil at the standard 100 deg c

https://www.jaguarforums.com/forum/xj-xj6-xjr6-x300-26/fan-relay-110742/