My 2000 XJR's radiator fan recently started to run after turning off the engine and got worse over the last 2 weeks. Fixed it by replacing the thermostat.



DETAILS:

Symptom / Warning sign:
Radiator fan used to not run after car is turned off.
Then radiator fan started to run after car is turned off.
Radiator fan ran for short amount of time then gradually ran for longer amount of time.

Fix 0:
Changed the coolant sensor.($7 ebay) Did not solve the issue. Fan still runs after engine is turned off.

Fix 1:
Changed the thermostat.($12 Autozone) Fixed the issue!!
TIP: Just undo the three 8mm bolts, no need to unplug the coolant hose.
The old thermostat's seal was no good. The old thermostat by itself looks alright thou.



My 2000 XJR runs fine now with 120K on it. I still need to check if it's got 2nd gen tensioners one of these days.


Hope this helps others facing similar issue.

 

If you have been on this forum for long you have certainly seen the warnings about a plastic tensioner failing and taking the engine with it.

But . . . let me say it again . . . the originally installed plastic tensioners have a very high failure rate and the result of jumping cam timing is often a destroyed engine.

Good luck!

 

I will add my voice to the choir- TAKE CARE OF YOUT TENSIONERS!

 

You seem knowledgeable and comfortable working on your car. Why would you not replace your tensioners before you destroy your engine?

 

Good job with the T-stat replacement! I had the same exact thing happen in 2004! The temperature gage was exactly in the middle & gave no warning. An independent shop checked out the car & said can find nothing wrong & it is "normal" for fan to run after stopping in hot summers. I knew that I had 3-4 summers where it NEVER ran after stopping. Despite 110+ temps. I learned on this forum that @~ 4 years regardless of mileage the T-stat often fails. I bought a genuine Jaguar one & replaced it & problem was solved.

What aftermarket T-stat did you buy & did you lose much coolant when you changed it?