When SWMBO got back from picking up the eldest at the airport her 2000 3.0 S-Type was showing P0171 & P0174. I can hear the leak. If I disconnect the breather at left rear of the engine the leak stops. It sounds as if it is coming from under the manifold so I am thinking PCV replacement. Sound correct?
I haven't had the manifold off for about 40K miles, so I am thinking coils, plugs, and PCV. What else should I replace while I have the manifold off - the car has about 135K miles.
Thanks,
Steve

 

There's a hose under there that perishes - see the many threads which include part # I believe. I think there may be another at the engine rear but I don't have that engine.

 

Welcome to the forum. There are a few things that you will need to do prior to becoming a full fledged member. I don't know if you will be able to view the link I provide but with in it you will find the answers to your questions.

Here's the link:
https://www.jaguarforums.com/forum/s...ics-faq-52720/

 

I thought the hose(s) that perish were unique to the early (OP's is 2000) 3.0 - are they on that pic?

 

Correct, but... In the first paragraph I provide a link to Gus's site ( JagRepair.com - Jaguar Repair Information Resource ) that explains in detail and pictures how to replace the "under intake elbow".

There is only 1 rubber hose elbow under the lower intake.

 

I had read about that elbow as well - but EEK - anti-seize on sparkplug threads? I didn't notice a reduced torque value so that could damage the threads in the head. The spec is for clean and dry, anti-seize could reduce the correct torque by 20% or more.

 

It is always a good idea to put a small amount of anti-seize on the spark plug threads when fitting the spark plugs as the head is aluminium and the spark plugs have steel threads.

 

We will just have to disagree on that, in my life I have seen far too many aluminum heads have the threads damaged by using anti-seize and then over torquing the sparkplugs (using the manufacture's spec). And it is a problem that keeps on giving as the next mechanic may not use anti-seize but there is enough left to strip the threads at the specified torque. But we are getting pretty far afield from items under the manifold.
Steve

 

That is very strange as I have never had that experience with using anti-seize on spark plug threads. Perhaps the over tightening is the reason for the damage to the aluminium threads?

You must do what is comfortable for you when it comes to servicing your own vehicle.

 

Getting OT but various plugs (e.g. the NGKs for my STR) come with an anti-seize coating and state that nothing else should be added. (And yes it would mean you should reduce the torque if you did.)

 

FWIW I recently completed what you are anticipating doing. I also changed my IMT O rings and my valve cover gaskets.

Also I had a vacuum leak at a rubber adapter at the left rear of the manifold. It was rotted a lot worse than the elbow underneath the plenum.

Search for my thread. One of the pictures has an arrow pointing toward the other adapter I had to replace. The part number is also in the thread if needed.

Good Luck!

 

If you mean the one at the left rear of the engine on top of what I think is an oil separator - that is where I first though the problem was. Unfortunately it is in excellent condition. I'll look up your thread, part numbers would help since I am 2.5 hours from the nearest Jag dealer.
Steve

 

I have an excel sheet that I converted to pdf I got from the Cadillac Lincoln site with step by step instructions that were awesome to get me through the removal of the plenum, and down to the bad elbow. Surprisingly, Ford charged the most for the replacement, a Jag store in California turned out to be the cheapest, use the part number and description, include in " marks "s-type" and you'll get better goog results. if you use the - key as, in s-type, google thinks that's a removal of the word "type" from your search function. If you want the pdf message me and I'll get it to you.