I think I'm in the same exact boat as you. I replaced the thermostat housing and there is still a small leak (much less than before but still leaking) I might try some UV leak detector.

 

My leak isn't drops of fluid, it is coming out (under the car, between the engine and transmission) at a steady clip. I do not have the replacement hose yet, but will pull what I can and post pictures. Since I just had the throttle body off (and then back on) last weekend, that shouldn't take long! My only concern is getting the intake manifold off. I hope that goes smoothly. My intent is to undo the four nuts holding the two frame rails, then remove the intake manifold bolts and see if it will all come up enough to reach the hose fitting.

 

Mine is barely leaking at all but enough that I can smell it occassionally and have to add a bit of coolant every couple weeks.
I think there is a special tool to remove the fuel lines that you can buy at most auto parts stores.

 

I have access to the other end of the hose now (at least I think I do. . .I'm going to wait until I have the new one in my hand to remove the other end).

I removed the throttle body, the thermostat housing (both parts, which I had just replaced last weekend), the metal portion of the intake manifold, and then disconnected the wiring harnesses running along either bank of cylinders. I then removed the bolts holding the intake manifold in place. I was then able to raise the intake manifold/fuel injector assembly high enough to get my hand in and feel the hose. It appears to run aft initially, then it makes a U turn and attaches to the rear of the base onto which the smaller portion of the thermostat housing bolts. If I could figure out how to post pictures I would (or someone might tell me how ). More once the replacement hose arrives.

 

Is the intake gasket metal? I'm wondering if once it's popped if it needs to be replaced. I'm guessing the hose from the throttle body has one of those clamps that you put on with the special pliers like the other hoses. I noticed some of the new hoses I bought have those clamps you can squeeze with regular pliers on them; some of the others I put the old screw kind on.

 

Yes, it is metal and should be replaced (I still haven't completely solved my vacuum leak; one thing you do not want to end up with at the end of this process is a vacuum leak since there are so many places it can come from). They have small tabs you bend to hold it in place while you lower the manifold back onto the heads. However, the replacement gaskets I purchased (not from the dealer, I think it was Autopartswharehouse or Rockauto) had smaller tabs, so they didn't hold them on that well and I had to do it several times (used tape on the tabs I could get to to remove the tape afterwards).

The hose is held on with the small clamps you have to squeeze (I hate those things although these were small enough a pair of pliers are okay).

 

That hose just sprung a leak in my car, 2008 XJ8 L, 48,000 miles. I've put off trying to fix it for a week, maybe this weekend I'll work up some courage.

 

It took me 8 hours to get the intake manifold out. The dealer wanted $500 for the job, I paid $29 for the hose at the dealer part number AJ81176, (I've since found it online cheaper) and $78 for two gaskets at AutoZone.

 

Unless you know the newness of the thermostat tower and return pipe, I would recommend that you also replace it. Prices are $60-100, but is much easier where you are now than later. Many failures recently, and I'm doing one myself, with hairline crack in moulding where you cannot see until you remove.
Can't understand why it is plastic on the NA, but metal on the XJR.

 

Thank you! Do you know if either can be replaced with metal ones?

 

I'm not aware, it was an option on the X308 series, but pipe arrangements are different on the X350 NA and SC versions.

 

Stella--------------sorry, the metal version is not available for the 05 -08 XJ8L.

Why? I don't have an answer..............

Cheers

 

It is a good idea to replace the thermostat housing each time the coolant is changed as the plastic housing can only stand a finite number of cold and hot cycles.

The housing assembly includes the thermostat and seal. There is no aluminium replacement for the 4.2 litre NA thermostat housing.

 

lol ,I just don't even get surprised any more when small things happen to this beautiful car that cost me dearly if I don't fix it myself.This sounds like my problem at this very moment,I was on track to change thermostat,then notices housing needed to changed.Now i think about it ,the car was leaking from above,then running down the transmission .I'm convenced its that $10 hose also,I haven't went under manifold yet,I think I'll call mechanic for this bad boy lol.Mind as well change that hose.I love this car ...........

 

what is the name of the hose that runs under manifold?

 

its nick named the valley coolant pipe .
also known as the throttle body coolant pipe and also known as a part no#
but you would need a specific part no# for your model and year as there are a few different ones .

 

Aka valley hose etc - some searches should turn it up with write-ups & pics. (It has some names I can't post, too. Not Jaguar's finest item.)

 

RE: Fuel Line Connector: ...Fuel line connector for xj8 X308 series is a ford style quick-release tool, available at any autoparts store, such as Autozone. Same connector used on all Fords of this era.
Important to know how to do, because this critical knowledge to have, if you ever have to replace your fuel pump (which is inside the gas tank). If need be you can create one of a piece of metal tubing.

 

I am also replacing these hoses
Do you need to remove the throttle body to remove the air intake manifold.

 

Afraid so, i .know i had to.