Last week the cap on my plastic thermostat housing had a small leak. Time to upgrade. Purchased a new aluminum housing from WELSH ENT. with thermostat, a real quality piece. All went well until the rear bolts, ended up heating and bending an open and box end 8mm wrench finally decided since I was trashing the old housing just knock off the rear tabs and unscrew the bolts, worked great. Decided to grind the rear bolts down about 3/8" to better clear the front of the intake, that worked great also. All the bolts went back in pretty easy, except the rear passenger side, took forever. Using the bent open end and about a 1/8 turn each time finally got it to where the modified box end could be used to tighten it down. so, if you are planning on doing this its not a quick project, just take your time.

 

It helps to take off the metal plate on the front of the plenum. I did it when I replaced my Tstat housing on my 03, gives you little bit more space ya need. Made it much easier to get to that pass side back bolt. I just bought myself a set of ratcheting wrenches that had the bend most make themselves, as you did here, figured I will need them eventually for other projects. Since owning two of these cars over the years I am coming up with a nice tool collection.

 

Your 03 is a different design. For the x100 I use socket head cap screws, which can easily be tightened with a ball end wrench (allen type).

 

Will a crows foot open end work? (3/8) drive

 

Yes, it should work. I guess you can check the cover on the front of your intake to see if it can be removed, as mentioned above, mine was not removable 2001, that would definitely give a little more room.

 

I used a 8mm crows foot attached to a flex shaft 3/8" drive.

The hardest part was finding a 8mm crows foot, all the sets I saw start with a 10mm. Ordered one online for a couple bucks.

I replaced the bolts with cap heads just in case I have to do it again!

 

A good way (other members and me went) is to destroy the brittle plastic housing, then there will be enough place to remove the screws.
For refastening fill or mill a slot in the screws and use a screwdriver.
It works.

(Sorry for my English)

 

But if you break the old housing then Murphy's Law states the new replacement part will either be the wrong part or defective. The probability of this happening goes way up if the Jag is your only car.


Dave

 

Didn't have a problem breaking off the rear tabs, new one fit perfectly and I guess it would have worked out because I had the XJR sitting in the garage.

 

Newbie here, great info! Thx