My 07 XJ8L with 62,000 miles began displaying the following symptoms:

1. Radiator fan blows even after short drives, and continues blowing for a few minutes after the car is turned off. Blows hard after longer drives.

2. RPM at idle (e.g. complete stop while in Drive) is 600 RPM whereas it's usually 800 RPM

3. Leak (reddish - possibly coolant) when symptoms first began, but no longer leaking

All else is fine. No check engine light and temperature gauge is fine. Coolant tank changed about 3 months ago and no issues with the new part.

Independent mechanic says he'll start with relays, while searching this forum suggests thermostat may be stuck.

I welcome your opinions ...

 

Knowing you had a coolant leak it must have been refilled

It is possible you have air in the system but my guess will be the thermostat.

On common reason for air in the system was the fill procedure was done without running the heater and you have a heap of air trapped in the heater core.

You wont see the temp guage move till it overheats however if you monitor with Torque or the liek you will see the correct temps.

The fan speed is controlled by the ECU and will vary the speed depending on how hot the coolant is but if its running more than normal its an indication of low coolant, air in the system or the thermostat. I could also be a bad coolant pump but they are rare to fail

Cheers
34by151