I literally just replaced my wife's 2005 XJ8L 4.2 (non-sc) valley hose yesterday:

https://www.rockauto.com/en/moreinfo...430955&jsn=627

It took some time and effort but is doable yourself. I saw someone post that they didn't have to fully remove the intake, just propped it up high enough to get under, so I did that :-)
The fuel line connection is flexible enough to get away with not disconnecting it. I did disconnect the wiring harness and injectors, but left the fuel line intact successfully.

Also bought the gaskets which are easy to replace as they have little tabs to hold them onto the intake (use a few bolts to ensure they are located).

https://www.rockauto.com/en/moreinfo...430955&jsn=658

The engine is super clean for 145,000 miles so it was a clean easy job, though without removing the intake fully the space to work in was super minimal. The valley hose was the original and the plastic downsize connection had broken. The new replacement I got is solid rubber, not going to happen again!

Also there was a thermo plastic foam insulation pack in the center of the block under the intake which I had not heard any mention of. There is also one running down the length of the left side intake. My center foam pack was saturated with coolant of course, but I stepped on it enough to squeeze it all out, and let it dry a bit before reinstalling it. It had been placed partially on the valley hose, crushing it down a little which had caused some damage to the hose. I made sure to not do that again and shifted it farther back. I suppose I could have just left it out entirely, but I think the engineering put it there to ensure proper heat distribution on the intake to help avoid cracking (?).

The car runs great with zero leaks! Yeah! I hope to get her past 200k miles as you did. Nice to know they have long legs!

 

Had to take my manifold off to replace those eight pesky rubber manifold gaskets.
The hose was still in pretty good shape, but being there, & a Jaguar hose for $20.
If my 07 ever needs either of the two done, I'll do both.
Those eight gaskets, kept throwing the dreaded, check engine light.
Mass air flow code, or a vac leak somewhere.
Car ran fine, and easily passed the tail pipe test.
But finally got it fixed.
Good thing too, no more tail pipe test.

 

Yes you are right, thank you very much for the good information, I really appreciated. I checked Michael Hamilton's post: https://www.jaguarforums.com/forum/xj-xj6-xj8-xjr-x350-x358-28/egr-valley-hoses-non-

s-c-149873/ . Very good job and that is exactly what is going on with my Jag XJ8 4.2L V8. I got the pictures and it s exactly the right explanation and I thanked Michael Hamilton for his nice work.






Throttle body return hose 4.2L part AJ811763


Inlet manifold off and see the Throttle body return hose

4.2L intake manifold diagram guide for the removal process

 

Yes you are right, thank you very much for the good information, I really appreciated. I checked Michael Hamilton's post:https://www.jaguarforums.com/forum/xj-xj6-xj8-xjr-x350-x358-28/egr-valley-hoses-non-

s-c-149873/ .Very good joband that is exactly what is going on with my Jag XJ8 4.2L V8. I got the pictures and it s exactly the right explanation and I thanked Michael Hamilton for his nice work.



Throttle body return hose 4.2L part AJ811763



Inlet manifold off and see the Throttle body return hose

 

That is exactly what is going on with my Jag. I drive it a lot ( highway driving, like 25,000 to 28,000 miles per year ) due to my job, I drive it to Texas then to Chicago , back to Florida and so on and still

have most of the parts from factory except the air suspension compressor and air shocks that I replaced with new Arnotts , battery , spark plugs and brake pads like the thermostat housing other parts

are functioning fine. it must be the highway driving that keeps the parts in action for an old jag and lubricated, I heard that the worst that can happen to an old jag is having it sitting without driving it.

Fluids are in constant circulation and that must be a good thing I think. I still have not replaced yet the pulleys or the tensioner , can you believe it !!!

I must say I went to see my mechanic ( a former Service Manager for jaguar that now has his own shop ) and he gave me an estimate including parts and labor for $980 plus tax and advised me about

preventive maintenance since my 04 Jag XJ8 has 228,200 miles and the Inlet manifold has to come off anyways for the install replacing :

-That throttle body return/valley hose,

-Thermostat Assembly,

-The 2 Knock sensors, left and right,

-The upper Inlet manifold gaskets ( 8 ),

He stated that it would be advisable to replace them since I won't have to worry about those parts for like 10 years maybe more and I said OK, since most Jag dealers charge you $500 to install Spark

plugs or a water pump install for $700, I think his price was OK and I don't have to deal with all the work for this time . I will put the money on the credit card. I also thought that most people pay $1,000

for an apple Iphone why no investing some less for my Jag for once, it's a car that take you to places it is worth the expense.

 

If you have such a good mechanics and fair price, it's worth doing it, your car will thank you

 

Just a guess at how much your paying, & for what.
$100 for thermostat assembly, & hose.
$100 for 8 gaskets, $80 now on computer.
$300 for the 2 sensors, only a guess.
Would think less than that on computer.
Never looked at their price, could be way off.
Price of $500, in parts, plus the same for the labor.
Pretty good price, for a real mechanic to do the job.
Going rate is to typically, double the price of the parts to the customer.
Then add the parts actual price, as the labor charge.
The opposite of the way things really are.
But things just look better that way, to the customer.

 

I'm losing Coolant from the front of my Xj Jaguar portfolio 2010 plate... O/S.
Any ideas.
Many thanks Phil

 

Is your car the X358, or is it the newer model from 2009, called the X351, and which has the modern styling not the traditional ? If so, post in the X351 forum, you might get better answers.