Okay, my thermostat housing cracked on the top, front to back. I have the new parts in hand and will tackle the job in a couple of days. Time will be in short supply, so I am wondering if it is absolutely necessary to entirely remove the whole housing assembly, dealing with the hard-to-reach back bolts... OR ...Could I leave the "tower" piece, which is in good shape, bolted to the engine and only replace the top section, which is fitted on the tower and sealed with an o-ring, and held in place by bolting to the front of the engine? Hope this makes sense. I don't have a picture handy to illustrate and the later model housing is different that the early ones. Also the later model does not seem to be available in any style but plastic.

Thanks for any thoughts!

 

I don't know the answer, but am interested too.

 

If it is like my 03 t-stat housing just replace it all. Those back two bolts that are hard to get too, not so hard it you remove the metal plate on the front of the black intake part. Removing that plate lets you get to the back to bolts with some more ease. If you take that plate off you may want to run to your jag dealer and get a new gasket for that. I do think you can use the orig as you are taking it out but if ya got the time may as well replace it. I DID NOT when I did my housing.

 

and you are correct, pre 2003 you WILL NOT find the alum replacement housing. I looked everywhere before I went OEM. I figured if the orig unit went 96k then a oem unit will go that far again.

 

I agree about the plastic lasting long enough, especially since some of the aluminum versions can leak.

Still wondering about the downside to not taking the tower off.

 

The tower is easy. The base of it that goes on top of motor, the back bolts (back pass side bolt at that) can be hard to reach but if you remove the front metal plate from black plenum they can be reached with no issue. Just be care when taking out the screws that you don't drop one underneath the intake, that would be an issue.

 

At that age do the whole thing. I would also do the rubber hose under the intake to the throttle body as well. Youre half way there, but the intsake needs to come off for that. Besides, when you take off the front of the housing youre gonna find that the back is eith broken or about to be where the oring seals between the two pieces

 

Do you have a photo of it?

 

Ahh, I did this, PANDORA'S box once the intake is off. Taking apart the TB to get intake off, then all the seals to put it all back together. There are two hoses under the intake, then there is the octopus hose while you are at it, then the hoses to the EGR then back to the TB.

 

Thanks all!

 

How many miles on your 2005? I've read about the early XK8 thermostat towers cracking but I don't remember reading about the later ones. Did you go looking for cracks due to leaking coolant issues or did you find them during a routine inspection? I guess age and heat cycles will eventually cause problems for all of these plastic parts in the engine bay....

 

Done! That wasn't so bad. Using a bent 8mm held by vice grips, the back bolts came out pretty easily. Long-handle needle nose pliers helped with the unscrewing. A little snug getting the passenger side one past the front of the intake manifold, but not a big deal. The pics show where I had patched the crack with JB Weld, which itself split right along the line of the crack. The car has about 101,000 miles on it.

 

good work!

 

Must say, though, the job had me wishing the housing were like the old-style domed thermostat housing that was held on by two bolts, had one fat hose on it, and that was that!