I have a 2017 XF AWD with a 2.0 diesel engine. I must say the car is excellent and has been nothing but a joy. However, for quite some time it has had a P0128 code locked in. I understand that it is most likely a stuck open thermostat. The engine does run below normal temperature for quite some time before coming up to the usual halfway mark. It never exceeds that temperature, so I'm happy for that. However, I do realize that if it is stuck open, it could someday stick shut. Therefore, I have bought a new thermostat for it and plan to change it out.
Looking at the manual, it seems easy enough to do, albeit with four hoses and two electrical connections. However, they must have had their model engine on a stand, as in the car it seems like very tight quarters to do this job.
So my question is this. Has anyone done this particular thermostat replacement? If so, can you give me any pointers as to what peripheral items need to get out of the way, and tell me if it can all be done from up top, or should some be from down below?
Just want to get my ducks in a row before I take this on. This is by far the most involved thermostat replacement I have ever done. Hopefully, it only appears so.
I have seen several youtube videos, but none are the right unit and engine.

 

I’m in the same situation you are in as well, searching every where for information on how to do this while waiting for delivery of the new thermostat. Any info is greatly appreciated.

 

After looking long and hard at this task, and considering the lack of advice, I have returned the thermostat. It is not worth getting in a jackpot with hose connections, etc., being so inaccessible. I did notice that it "may be possible" to get good access through the wheel well, though the spring would be in the way. If I ever figure out a method, I will post it here.

 

So we're all on the same page...

 

I just noticed the clip left of center in the photo. I wonder if that allows removal of the left portion? That would make things a bit more doable. When you get your thermostat, let me know what you think.

 

I will do that, I think the part is due in 7/17. I flushed the coolant last week, but unfortunately you can only flush about half the coolant, the rest sits in the heater box and in the engine. So only put in just over a gallon on the refill. Will do it again when i take on the thermostat replacement. The Jag dealership said to diagnose it was $195, even though I told them the code was P0128.

 

I have the same issue on my 2017 2.0 D XF
I don't have the code reader but the temp takes miles to warm up - then ok.
I located the thermostat unit online and thought I would give it a go.
There is step by step instructions in the service manual which someone has posted on this site and can be downloaded for free.
You will need a set of hose clamp pliers available on amazon cheap ( $18.00 Canadian Dollars ) its a great tool.
That all being said I could not access the wire plugs to undo - perhaps needs access from below. I did get as far as removing the hoses - all 4 then gave up.
Ill drop it off for a mechanic to do it before winter.

 

This is the thermostat removal portion of the FSM