I was going to replace my serpentine belt as mentioned in a separate thread, and while doing so removed the vanity cover and the under scuttle for an oil change and inspect for leaks.

I pulled the vanity cover and moved it aside. Then removed the under scuttle. Oil all over the pan and worked it's way down from higher up. First thought was the left side VC gasket. I Turns out the oil filler neck has been leaking. Whew. O-ring was shot.

I broke the metal tang holding the filler tube in place so I'm ordering a new one on eBay. Part # AJ88581. As kj07xk notes in his write up about changing the left valve cover gasket, the o-Ring isn't sold by itself. I'm waiting on the oil and filter from Amazon so for the heck of it, I'm going to pop over to the hardware store and see if I can find an o-ring, but for any of you who find you have to replace yours, the I.D. is 1 1/16 inch and the diameter of the o-ring is 3/16". As I said, I screwed the pooch when I broke the tang that prevents the filler neck from self loosening, but if you have need and are successful, now you know the size.

 

OEM filler neck came today. Should be good for another 10 years. Cleaned off the engine, changed the oil.

 

What is the process to replace that oil filler neck?

 

As Sean said, he broke the metal tang off, I sawed mine off, as you just can’t get the thing to unscrew with that tang present.
I had a replacement filler neck, as that is listed as a part to be replaced when replacing the valve cover gasket. Apparently the way its designed, you have to destroy it to remove it.

 

Here are the highly detailed instructions on how to remove it. As you can see they are very specific and detailed. There should be absolutely no questions or concerns on how to remove the filler neck if following the procedure below. Hahahaha

 

The one on my Mercedes simply twisted off exactly like the oil filler cap, just lower down. Not sure how the Jaguar one is attached, but with the Mercedes I ordered a new one and looked at the replacement part and saw how it went on. I used my large channel locks to twist it off.

 

It does screw in/out, but they built in a metal tang/tab/prong that locks it in place. Need to cut or break off that tang to be able to turn it.

 

Is it actually necessary to remove the filler neck when removing the valve cover; or is it necessary to remove the filler neck only if the O-ring between the neck and the valve cover has started to leak?

Regarding the metal tang, I now understand it works one-way - hence you can rotate the filler neck clockwise to install it without the tang causing interference; but you cannot rotate the neck counter-clockwise to remove it without first removing the tang?

Thanks.

 

No it's not necessary for removal of the valve cover - yes only for replacement of the filler neck o-ring.
Thanks.[/QUOTE]
Well you don't/can't remove the tab I don't think. You pry it up a little and then continue turning counter clockwise, Once it's past the bump on the valve cover, it just unscrews. It's a flimsy tab though. I used a jewelers screwdriver and it still broke. I think being subjected to the same heat that the o-ring is, it just gets brittle. If yours is leaking, I would just plan on dropping the $30 for a full replacement. I wasn't able the find an o-ring anyway.

 

Since it was listed as a replacement part when doing the valve cover seals, I had purchased a new one, and that was before trying to remove the old one.
After I had removed the valve cover, I futzed with trying to 'safely' remove the filler neck, until I just said 'screw it' and cut off the tang.

 

I think that's why I made the assumption that the VVT seal required the removal of the valve cover. Re-reading your valve cover thread, you were just replacing all seals with the "well I'm in there now, might as well do it" thinking, and I interpreted the thread wrong, assuming the VVT and some other seals required the removal of the cover.

 

Not wanting to screw up my baby, I was just following the workshop manual to the letter. So there was a step that said to 'Remove and discard the O-ring seal.' for the oil filler pipe. Since I couldn't find that part, I just ordered the whole filler pipe, which came with a seal.
Probably wasn't necessary, similarly for most of the other seals (just bolts with rubber grommets), but I'm a 'good boy' and followed the procedures. In hind-sight, yeah, it was a good thing to do, as those rubber bits are old, and could cause unnecessary grief down the road.

 

Yeah good info Sean and kj07xk . Made replacing mine easy - pry up on the tab and turn. Mine didn't break. I got a new pipe also because it comes with the o-ring for the cap too. And a new cap. Should do both at the same time.

For S/C engines, re-position the purge valve bracket and hose. Makes replacing the tube much easier.

Just to be clear I removed the filler pipe and O-ring WITHOUT removing the valve cover. This was due to a vacuum/breather leak at the pipe. You can check it out on my DIY smoke machine thread.