Think my Thermostat failed open in the XJR today as it is at the first line free from the blue on the thermostat at highway speeds today. It will climb up when you are in town or at an idle though. Guessing it is open. Just read on a crappy car repair site that there are 2 of them which I don't see both failing nor don't know why it would need two but I went to windows 8 and haven't figured out how to get JITS on it yet. Can anybody confirm how many there are and what temp the stock one should be. Diagram would be great!!! 183 rings a bell for when I replaced the XK8 one. Anything hard about getting to it with the supercharger and all? Should have replaced it in August when I flushed the antifreeze but figured I'd replace it in 2 years when I did all the hoses as a couple are starting to show signs of expanding. Guess not.






Happy Thanksgiving!

 

Read my post, here-https://www.jaguarforums.com/forum/x...ts-xjr-100659/
It should have all you need. Changing it is easy. no access problems for the XJR. Make REALLY sure you follow the bleeding procedure to get the air out of not only the engine circuit, but also the intercooler circuit.

1. Refill the cooling system with a 50% solution of water and Jaguar Antifreeze / Corrosion Inhibitor
ESD-M97B49-A.
1. Remove the threaded plug and Dowty washer from the charge air cooler fill point.
2. Fill the cooling system at the header tank until the level stabilises near the top of the charge air cooler fill
point. This will take some time, as air is being purged from the system.
• Ensure that the header tank is full.
NOTE:
To ensure that air is not drawn into the system during the following operations:
• Do not remove the cap from the header tank whilst the charge air cooling system is open to atmosphere.
• Do not switch on the ignition when the charge air cooling system is open to atmosphere because the
electrical cooling pump may draw air into the system.
2. Fit the pressure cap to the header tank.
3. Pour coolant carefully into the charge air cooler fill point until the system is full.
• Fit the plug and washer to the fill point.
4. Remove the pressure cap from the header tank.
5. Switch on the ignition and switch off the climate control system.
• Leave the ignition switched on (do not start the engine) for at least 2 minutes to allow the air charge cooler
electric water pump to operate and to purge any air from the air charge cooler radiator to the header tank.
(This operation will be repeated later)
6. Switch off the ignition for at least 1 minute.
7. Leave the ignition switched on (do not start the engine) for at least 2 minutes to allow the air charge cooler
electric water pump to operate and to purge any air from the air charge cooler radiator to the header tank.
8. Top up the cooling system.
1. Top up the header tank and fit the pressure cap.
2. Remove the plug from the air charge cooler fill point. Pour coolant carefully into the air charge cooler fill
point until the system is full.
3. Fit the plug and washer to the fill point.
9. Run the engine at between 1500 and 2000 rpm until the cooling fans operate.
10. Switch on the climate control system, set to maximum heat, and check that heat is coming from the heater
at the fascia vents or the footwell outlets.
11. Switch off the engine and allow it to cool down.
12. When cool, remove the pressure cap and top up the system as necessary at the header tank.
13. If necessary, fit new seals to the pressure cap.
1. Remove both O-rings from the pressure cap.
• Fit and fully seat new O-rings to the pressure cap. Fit the pressure cap.
14. Check that the pressure cap is fitted. Remove the plug from the air charge cooler fill point. Pour coolant
carefully into the air charge cooler fill point until the system is full.
• Fit the plug to the fill point, using a new Dowty sealing washer.
Remove the paintwork protection sheets and close the engine cover.

I would add that you need to listen carefully to the intercooler electric pump, and squeeze the rad hose a couple times to make sure it's pumping water, not just spinning fast in an air bubble.

 

Thanks Rob,
Ordered an OEM stat from partsgeek. 2x the price as a Gates but it should be here early next week as opposed to mid next week from Rockauto or amazon. Kicking myself for not doing it 2 months ago when I flushed the system and put in dexcool.