Search high, search low, I can find almost nothing on thermostats and sourcing. Elsewhere, I figured out that the 4.2 takes a different t'stat than the 4.0s, but as to a suitable non-Jag source guaranteed to fit, I haven't found anything. There isn't anything on the list on interchangeable parts! Can anyone offer advice as to a reliable, correctly fitting source?

 

I think motorcraft has one (part number 645-01184313) ..after doing some googling that's what I came up with.. you could probably google that part number and go from there..

2003-2006 Jaguar XK8 Thermostat - Cooling System - Motorcraft 03-06 XK8 Thermostat - 645-01184313 - PartsGeek

or for about the same price you could just get a factory OEM one.. or google the factory part number.. (AJ8-2697)

Jaguar Thermostat Assy, Most Non-Supercharged 4.2 V-8 - AJ8-2697

Not sure if that helps :/

 

FWIW, I would recommend you get the entire assembly. It is all plastic, so your is likely to be 12+ years old. If it breaks, you are stranded. The assembly includes the pipes, o-ring, thermostat and sensor. It is about $100 for the whole thing, so not excessive for what you get.

Obviously, your car, your wallet, your decision.

 

Certainly it helps; Thanks! I note the word 'kit' in the Jag part. Please tell me that I am not looking at replacing an integrated housing / stat with MAP interface

 

Unfortunately, I get no result when I Google that p/n (Motorcraft 645-01184313). Are you certain of the number Mathew?

 

Ouch Smertz! That job just went up by a factor of 10 or so. So it IS possible to replace just the stat? The trouble is that having bought the car last summer, even with some Jag records from the previous owner, I don't have a clue if even the coolant has ever been changed. Also, I don't know that it wasn't done just before the last owner purchased the car some 2 years back. If Jag was involved, I imagine they would have pushed for the full treatment. I hate to do work that doesn't need doing, particularly if it costs a lot of money.

 

well I *think* that's the part number.. that's what they have listed if you click that first link - but yeah it should be correct.

But you're right I googled that part number too and it's not coming up.. mm.. that's a toughie I'll keep looking.

(honestly I'd just get the Jag part unless someone online here knows a part that works on it but I don't think that's a ford thermostat or anything like that.... you're looking about the same price.. I changed it coolant on mine last summer and it was a bit of a pain since mine is a XKR but changing out the thermostat was pretty easy.. )

 

suggest you use "search" function on E-Bay and enter the OEM #. it should bring up some Jag sources that sell at reduced prices. jaguarpartsplace is one of them.

 

I concur with fmertz's recommendation to consider replacing the entire coolant pipe plastic assembly (which includes the thermostat). It is made from relatively lousy plastic and they all eventually warp and begin to leak, often at the thermostat housing. I went through this in November 2014 with my wife's 2006 XK8 and took the advice of those who recommended that I replace the entire plastic assembly (which I paid about $125 for on discounted pricing at the local Jaguar dealership parts department). If you have no documentation that your assembly has ever been replaced, just bite the bullet and do it. That job may save your engine one day....

 

So back on the p/n search in case I can't 'see' the $125 upgrade, I have a Stant number 49499 coming up, and their website states that this fits the various V8s of the period. This is what it looks like. Can someone confirm that it at least looks like the right part and also comment on the rubber seal, which I don't see in the image. Is this a separate purchase? Thanks!

 

On a slightly tangential path, has anyone ever tried out a lower temp stat such as this one:

Jaguar Low-Temp Thermostat - Jaguar Performance Parts, Eurotoys Ltd.

When I had my Corvette one of the first things everybody seemed to do was to install a lower temp stat and also program the radiator fans to come on earlier. The running temps dropped dramatically when I did this with no ill effects.

Doug

 

According to the Jag parts catalogue:
Thermostat is AJ82697
Entire housing (which comes with a T/stat) is AJ89486

Hope that helps. The XK8 parts catalogue is online now at http://www.jaguarclassicparts.com/

 

Are all of you *** uming that he has a plastic housing? If it's metal why are you changing the thermostat in the first place?

 

If you have a plastic thermo housing - I'm with Freddo, get the metal one and you'll sleep a lot better. Motorcarsltd.com has a thermostat -

Jaguar Thermostat.

They say they have a housing too, but it says to call. I'm surprised it is hard to find a metal housing. I replaced the plastic one on my XJ8, but that was a 4.0, and the 4.2 one looks different (or maybe it's a generic picture on Motorcars ?).
I saw a thermostat at Rockauto also, (49499) but it was actually more expensive !

 

Well, not sure what to make of the poor response to the chat line at Motorcars Ltd. I got a quick enough connect with someone, gave them the SKU, asked the questions... Be right back... nothing. 15 mins later I sent them a 'chat' with the email address to send particulars to, but it's not encouraging. When I asked Welch about this they definitely said that there is no such animal for 2003-2005, so presumably the configuration is completely different. Who do we know who has bought a metal version for the 2005 XK8 and where was it purchased?

 

Running a 160*F on mine. The needle sits more than a full mark
below half and still goes into closed loop. It will sit there unless
I am in slow traffic for a long time because I have not modified
the fan on programming.

Unlike the Eurotoys version, it is closer in the match of the bypass
disc and it is off the shelf. Not "specially modified" as Eurotoys claims
about theirs. I have doubts that they did anything. They just did what
I did ... matched dimensions using a thermostat application catalog
using the original dimensions seeking a thermostat with a different
rated opening temperature.

Mine is much closer to the original Jaguar Waxstat and is made in
Germany.

 

Do you have a link for the thermostat or where it can be bought?

Doug

 

To my knowledge there is still no aftermarket metal coolant outlet pipe / thermostat housing assembly available for the 4.2 engine. Maybe one day....

 

You make it sound like such a conspiracy. We started selling these about 14-15 years ago and YES, we did have to modify the thermostat itself for them to fit into the aluminum housing. Since then, that Thermostat was redesigned and that modification is not required anymore. However, every once in awhile we get the old design and have to modify it.


Mike