Hi guys, need some advice on replacing my thermostat/housing on my 2007 Jaguar XK (not R).
I have read a bunch of posts about it, pretty common problem it appears as the gasket gets old, compresses and impedes the thermostat from closing fully when the engine is cold. Good news with this problem is it does not result in overheating.
I get the common error code: P0128, after adding coolant (not much) and resetting it, the code returned the following day, so I guess it's real.
I haven't been able to find the frequently referred to replacement guide/walk through, but thats ok I have the digital manual and see the process. Looks straight forward. Does anyone have a link to a youtube or a better guide with photos/video of the replacement?
A few more questions, while shopping for an OEM replacement, many sales show the same housing and thermostat fit multiple Jaguars. It that true?
Does anyone have the actual part numbers for it so that I can cross reference it?
Looks like OEM can be had for around $160 best pricing, but I want to make sure I get the correct part for the 2007 XK (not R).
Also, the housing looks to be high on the engine, do I still NEED to drain the coolant system?
The reason I am asking is that I am about to trade this in on a newer jag and would like to minimize the work and money spent to repair and I just flushed and replaced the coolant about a year ago.
Thanks for the help!

 

Last time I researched thermostats I could not find anything but the OEM. Best price I know of is at Columbia Jaguar: https://oemdiscountcarparts.com/part...&siteid=218637

Sometimes thermostats become "stuck". If it is stuck in the closed position, you will overheat - the engine itself will be very hot, and the radiator comparatively cool.

 

Thanks, and yep, I'm aware of how the thermostat works and I'm not overheating, so I know it isn't suck in the closed position (thank goodness, or the car would be parked).
Thanks for the link, is that just for the thermostat? At $51 that seems cheap compared to others... seems everyone has been recommending replacing the entire housing with the thermostat at the same time.
Thanks again!!

 

Ditto. the molded rubber seal on the outside lip delaminates causing the T-stat to leak past or bind in the bore.

 

Good luck trying to replace just the thermostat its pretty much a sealed unit and due to the housing made from plastic it's brittle, usually in bad condition and will break if trying to dismantle

Save yourself the headaches and replace the entire unit

Word of note the job is fiddly just make sure you have torx bits also a new gasket for the throttle body as that will need to be removed for accessibility.

Happy wrenching

 

Also, be prepaired to remove the underbody engine cover to retreave T-body bolts that you'll probably drop in the process. Not a big deal but pretty hard to see/feel when reinstalling the parts. I do agree with simply replacing the entire molded plastic unit as they have a record of disentigrating internally and those pieces are aiming for the water pump/engine as a result.

 

https://www.jaguarforums.com/forum/p...gasket-191208/

The seller is a tech on this site so you can confirm it's what you need.

 

Ugh, that I ordered the part, it was just the themostat and not the housing!
Dangit.

 

AJ811793 is the outlet pipe (incl thermostat and engine coolant temp sensor) that I bought in April 2017 when I replaced that part on my 2007 XK. The price was $123.24 plus shipping.
AJ88430 is the throttle body gasket. I paid $2.34 plus shipping.

Regarding the coolant drain, just drain a gallon directly into a clean container, then you can put it back into the system when you have replaced the outlet pipe - if you are concerned about buying fresh coolant. Or you don't have to drain the system if you want to remove the outlet pipe and let whatever coolant quantity (perhaps 2 quarts) come out of the engine and spill on your garage floor.

It's not that easy to remove the Torx bolts holding the coolant pipe to the engine. Also I hope you have a suitable tool to loosen the affected hoses without causing damage to the rubber. I replaced the hoses at the same time, so I just used a razor blade to slice the rubber and pry the hoses off.

Good luck.

New vs. old coolant outlet pipe

Old coolant outlet pipe disengaged from engine. Throttle body removed for access.

Another view of removed throttle body

 

Hi, I have just completed this task on my 2007 XK (not XKR) and found this thread useful.

I am based in UK and used Halfords OAT coolant. I did not drain coolant before work as you do not loose much on this job. When job is complete just top up coolant at reservoir and follow Jaguar workshop manual to bleed. I used Berkshire Jag Components in UK for thermostat and throttle body gasket.

Here are some images that may help people in future: -


Bonnet in access mode. Disconnect gas struts and prop open or bolt through hinges.


Engine cover off. Need to disconnect big top hose from throttle body and airbox. Power steering reservoir is moved out of way during this.


Improved access. Throttle body needs to come off. Make sure you have new gasket.


Throttle body removed. New parts alongside old parts (you can see old thermostat housing if you look close). This is a good time to carefully clean throttle body. Do not damage coating. Use new parts to work out where bolts are located that you may not be able to see.


I hoped not to need to remove any more parts after throttle body but when I removed throttle body the thermostat housing part that connects to engine had broken face so I had to remove that too. Access to those 4 x vertical bolts means throttle body inlet to engine must come off. Be prepared for this as parts are old and brittle. Its not a lot more work it turns out. 4 bolts for inlet and 2 for EGR pipe.


Note EGR pipe that needed split. Bolt access is tight but not terrible. Good to have ratchet spanner set.


Throttle body housing and intake fully removed. I did not replace the green gasket but be sure to give a good clean to it and all mating surfaces. I also reused metal EGR pipe gasket after cleaning it.

 

Good work

I tend to swap mine out every 5 years pretty much the same time I change my battery on my 3rd thermostat now ..it's a shame we didn't get the aluminium housing like the r models