I think I know the answer to this question (unfortunately) but worth getting confirmation from the experts here ..................
my next project is to replace all the coolant hoses on my car - after 17 years and 120k miles, I suspect they are starting to degrade.
If everything at the front of the engine (thermostat tower, top hose, bypass hose etc) and everything at the back (throttle body, heater pump and valve etc.), are removed, is it possible to sort-of "thread" the two valley hoses under the intake manifold without removing it ? Would obviously save time and money (on gaskets etc) but I'm also wary of disconnecting the norma fittings on the fuel pipes and all the injector wiring.
I think the answer is probably a resounding "NO" but worth double checking !
Thanks,
David.

 

Well, here it comes...NO. Not in my view, anyway.

There's a large block of foam-type material that sits on top of the engine block and underneath the intake manifold. It has grooves formed under it to accomodate the valley hoses, and it's a tight fit.

When I did the same work, I invested in the gaskets and took the entire intake assembly apart...manifold, throttle body, induction elbow, etc. I cleaned everything up nicely and learned a lot about my engine.



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I did mine as preventative maintenance last year. It actually isn't difficult to remove the inlet manifold - just work methodically, and from memory there is only one fuel line that requires a disconnect tool. I replaced all the manifold gaskets and TB elbow gasket at the same time - good to cross those off as replaced too. The most awkward bit(for me) were the fixings on the TB elbow - P.I.A..

 

I would remove the intake as well. Did mine last summer and also do the coolant tower which you can get aftermarket in aluminum rather than plastic. The back bolt is nearly impossible to remove without taking the intake off.

 

You won't be able to get one of the hoses off without removing the Manifold. You already did the hard part. it's a good time to clean the gunk from the top of the engine.

 

Gentlemen - thank you.
In some ways, I'm not disappointed that there's no short-cut - I prefer to do a thorough and comprehensive job. But ......... I know from past experience that nuts, bolts, clips, bits of plastic, connectors, pipes, hoses and wires that have lain undisturbed for a long time have a habit of fighting back if someone (me !) starts attacking them with a spanner and a lot of colo(u)rful language !!

 

You're right...but most of those deteriorating parts should be replaced anyway, especially on a 1997.

Do yourself a favor and go ahead and order a Part-Load Breather hose now...it runs from the left valve cover, underneath the intake manifold to the induction elbow, and then to the EVAP system I believe...you WILL break this old piece of plastic as you disconnect it from the induction elbow. Luckily it's not expensive...your part number is AJ84880. It's available in the US for about $25 USD.



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Maybe - maybe not .................
I have already removed the part-load breather pipe to make sure it was clear - managed to get it off and on again without breaking it.
But .......... probably won't have the same luck second time around !!

 

I'm with The Coupe. I just finished replacing the valley hoses and I replaced all of the other tubes and connectors given my XK8 is a 1999 what didnt break in the process will soon anyway. A good investment in the long run as opposed to being left stranded somewhere or having to go back in to deal with something later. Here are some pics of my work and I replaced the thermostat and housing while at it

 

Does anyone have a part # for the valley hoses?

 

on my 99 xk8 they were NCA3945CD and NNE3946CA

 

11 years later and your comment saved me. I just removed my intake and all to replace my valley hoses, and the Part-Loader Breather hose is the ONE THING that was broken. Saved my life listing the part #, brother. Thank you! 2001 XJ8 Vanden Plas.

 

I had a leaking valley hose and replaced every rubber hose. Did by tilting manifold up and not removing.
Hints:
1. the octopus hose is held in by a zip tie you can’t see;
2. get hose clamp release pliers including one with extension cables;
3. heater hose to firewall will look partially kinked; 4. hose pliers a good idea;
5. cut old hoses lengthwise at connector to ease removal;
6. Silicone spray to slide on;
7. Bandaids for knuckles.
My thread at: https://www.jaguarforums.com/forum/x...r-hose-288201/