I've seen several threads about the fans running too much but mine seem to run too little. I started paying attention to this a couple months ago after finding a puddle under the car and reading about all the water pump, thermostat and temp gauge issues. I've only owned the car since April. When I get home throughout June and July I open the hood with the engine still idling and the fans are usually running on low as expected. When I turn off the engine I hear a few clicks like a relay is trying to do something but no fans. I usually measure the temp with an IR gauge at the thermostat housing and have been seeing temps in the 190 to 210 range. Other than the one puddle experience there are no visible coolant leaks but I have to top off the reservoir about once a week and there is a frequent coolant odor under the hood. Also, I find the upper radiator hose partially collapsed some mornings -- usually the same ones where I add coolant to the reservoir. I tried the 100 ohm resistor in place of the sensor trick and did get the fans to run on high but only while the resistor was in place. I've replaced the temp sensor and also measured the resistance of the old and new one and they appear to match the specs. This doesn't seem like it could be the radiator, water pump, fan motor or other common cooling system maladies...

 

<Can a moderator move this to the XK8/R section>

Your temps. seem in the normal range.

This thread discusses some possible reasons for a collapsed hose: https://www.jaguarforums.com/forum/x...or-hose-62028/

It does sound like you have a slow leak, however, so a cooling system pressure test would also be well advised.

 

An update on my fans. I've been watching the temps with Autoengenuity and now with my newly installed Realgauge modification. WIth the engine running the slow fans kick in at 205 and kick out at 195. The fast fans never run other than when I put the 100 ohm resistor in place of the temp sensor. I did replace the upper radiator hose and thermostat as they were such easy and cheap updates. No more collapsing upper hose and I haven't seen any loss of coolant in a while so the only remaining mystery is why the fans don't run after shutdown. Since there are no other symptoms of overheating I'll probably just move on to another adventure like fixing the steering wheel drop motor.