One of the 96's sprung a leak. Near as I can make out, it emanates from where the water rail (the tube the aft-end of the b*st*rd hose connects to) is affixed to the engine. Whether head or block I can't really make out, too much junk in the way.

I replaced ALL coolant hoses several months ago. Coolant is running down the side of the engine and dripping off the oil pan. I can't really find anywhere else it may be coming from. Anyway, I can't find a procedure showing renewal of the water rail gasket. My X300 disc Engine Unit Service manual refers me to sec. 4.1 of the VSM for cooling system issues. THe VSM covers Radiator, cooling fan, and little else. I could swear I've seen drawings of how that thing mounts to the engine somewhere. Is it a gasket? Anybody got diagrams?
(I haven't checked JTIS yet, have to dig out and power-up another computer for that, maybe that is where I saw it)

 

The bypass pipe is a simple bolt-on to the block, 4 bolts, 2 gaskets (for two passages into the engine).

BTW the Dayco bypass hose is part #71666 and is now also known as the DEVIL hose.

But it's a peach if you already have the manifold off!

 

Perhaps this is the diagram you have seen?

Water Rail-3.2/4.0 Litre - Parts For XJ Series from (V)720125 to (V)812255 (X300) | Jaguar Classic Parts UK

 

My water rail connection leaked about a year after I replaced the hose. Tightening the clamp took care of it, but there was a lot of corrosion on the nipple when I did the replacement, so getting a good seal is not easy.

 

Thanks for the pic, Richard....I had hoped to avoid removal of the intake manifold...but hey...we got the car with 105k on it, has about 107k now..guess it's time for a cleanout anyway, eh?

Brendan, that diagram does look familiar, I think it may be the one I was thinking of.

RJ, my leak is not at the hose connection, that is still good and dry. Have done two of those bypass hose replacements now and nipple-cleanup is key. I found about a 2" wide strip of sandpaper, a full (length or width) sheet long to be an excellent tool for cleaning up the forward end of the water rail - but you have to get it good'n'dry first or you'll just rip a lot of sandpaper into little 2" X 3" strips!

 

You don't need to remove the intake.
It CAN be accessed but you will need to remove the air pump and the little curved bypass hose. Get a new curved bypass hose (EAC3803) if it is there (might just be the XJ40??)

The water rail to pump hose (NBC2273AB) usually SPLITS and dumps coolant.

The XJR is the one you really don't want to do. The XJ6 warranty time is LESS than 2 hours so Jaguar thinks it is a simple job.

A long 1/4" drive extension with a universal joint socket will get the clamps. I can sometimes get the rear one through the intake 'runners'. A razor knife for the hose will ease the removal and some rubber grease will help with installation.

bob

 

Thanks Bob!
I just renewed that hose at the end of January and a little over 1,000 miles ago. Guess i could order another one, Spruce will need one...but I would hope to be able to change out the gasket(s) and re-use the hose. Near as I recall, I don't have the little curved hose.

Is it two gaskets/rail? Richard says so, in his post above with the very helpful picture, and eBay listings for the gasket say you need two/car, but the drawing only shows one.

So far, I'm looking at Terry's or Parts.com as best overall price incl shipping.
Within a dollar of one another for 6 pcs (figure may's well get enough to do all 3 cars) at $23-$24 incl shipping.

 

Like Bob said, I removed the air pump, then used wet/dry paper strips with water to improve cutting. I can see where having to replace the gaskets requires manifold removal.

 

I don't remember removing the water rail on the AJ16.
I did replace one on a 3.6 AJ6 installed in a 1985 XJ-S.
I think I did need to remove or at least displace the intake manifold.
Too many beers and years to remember all the gaskets I've replaced!!!!!!!!!!!!

bob

 

Funny, that JCP diagram only shows one bolt! I recommend 4 bolts and 2 gaskets.

Looks like you're the guy to give it a shot, without manifold removal. For the good of the Forum! Thank you in advance! :-)

 

I've ordered 3 Intake manifold and 6 water rail gaskets. Surely the bolts are reusable?
Poked around both 96's last night using a collection of mirrors and my borescope camera, I'm persuaded the intake will need to come off - despite all the visual tools, I could only lay eyes on one of the four bolts, even knowing where they're supposed to be!
The actual leaker is fully assembled, the other one has the air box and and ducting all the way to the intake casting removed, as well as the cam-cover. Both front ends are raised some - though I wasn't dressed for rolling around in the coolant under the leaker nor the oil under the other one. So it may be more clear from underneath, but I doubt it.
Will post results after parts and time come together to effect a fix.

 

You might get away with pulling the intake away from the head with ratchet straps and getting to the fasteners with flex/wobble tools. I usually pull the heads with just holding the intake/exhaust with ratchet straps. Enough room for head removal but maybe not for water rail????

bob