Sensor is something we're suspecting as a possible source of the problem.
I went and bought one to see if that would fix everything... hopefully... finally

You better believe it's real. When needle is in red, vents start blowing hot air
and in addition to 30C outside, it makes living heal inside

 

What do you mean by, even new blower?

 

Well, there is little fan that pushes hot and cold air in saloon to keep it comfortable
inside in the summer and winter commonly called "blower" which we have to replace
because it has bad bearing.

 

I think the blowing hot air is a fail safe determined by the temp sensor/ecu. When the coolant reaches a certain point as read by the temp sensor the AC turns off. So if you have the AC running it will just blow hot air. That does not actually mean the car is overheating, it just means the car thinks it is. As I mentioned before, I would figure out how to read the data straight from the sensor itself and pull some temp readings off of the radiator. Check the upper and lower hose temps and across the radiator itself.

Otherwise what was cause or original problem that resulted in you replacing all of these parts? Were any of these confirmed bad before you started replacing things? Did a mechanic suggest doing all this work?

It looks like you also had an overheating problem last year. What was the result of that?

 

I'm having same problem only LS engine so I've replaced radiator, fan controller, all hoses, heads off and resurfaced (they were warped), new head gaskets, taking water pump off now to replace....even wired the fans to run any time ignition is on. no water in the oil and no steam out the exhaust! Your problem sounds like air flow (cool when driving over heats when sitting)... could be bad fans, bad controller or obstruction in grille...believe me I understand your frustration. My car had blown head gaskets when I got it because the fans weren't even turning. I doubt the previous owner even knew what caused it.

 

This may sound silly, but are you sure ALL the air is out of the system? Was it filled with a vacuum filler? If there is still air in the system it will not flow well at idle. But will flow better at higher rpm combining increased air flow with movement will run cooler. Air in the system will also wreak havoc with the temp sensor. Modern cooling systems aren't always strong enough to push an air pocket clear.

 

+1 on the above.

The only sure way to fill these systems is with a vacuum filler. Has been stated in several threads.

That is how I do mine.

 

Raising the front end a few inches while running, can often help to burp the air out.

 

I am fairly certain the cooling system in the Jaguar automatically removes air. I have had my system apart a few times and never had to do anything other than run the car a bit after I had the system connected, and gradually add coolant after a couple of drives. AllData states that it can be done both ways. The only special bleeding instructions are if you drained the SC system. I would argue that if your system is not purging air automatically then you have a block somewhere that is causing some additional headache.

In fact, here is some additional info as it relates to the expansion tank:

 

Just sayin.