I finally smoke tested our 2006 XK8 with 4.2 NA engine after continually getting bank 1 and 2 lean codes. Sure enough, leaking of the base of the oil filler tube and also the 2 vacuum fittings at bottom of throttle body. Surprisingly the hard plastic line is ok, with no cracks. So two questions:

How to remove the oil fill tube to replace the o-ring? Appears to unscrew but not backing out and don't want to break it. Is that tab on back locking it in place?
I assume there are O-rings in those fittings at bottom of throttle body, but how do you even get to them, much less remove them?

Thanks,
Doug

 

Concerning the oil fill tube, there is a locking tab on the inside of the valve cover that needs to be gently adjusted to unlock. So the right way would be to remove the valve cover to unlock it. If you decide not to go through all that, the lock will be broken and every time you to go to add oil, the oil filler cap and tube will turn as one and you’ll need to remove the engine cover as the base of the tube will be wider than the engine cover. You could also keep the engine cover off and just put the oil filler cap directly on the valve cover but, it’s your decision.

Concerning the brake vacuum supply hose at the intake plenum, you’ll want to replace the plastic release and the special o ring that’s inside. Once you try to get the o ring out, that plastic release will break. Given the age and mileage of these cars, there’s only 2 types of plastic, broke and almost broke.

 

There is no need to remove the cam cover. There is an 8mm nut holding the dipstick to the cam cover. Remove the nut and pull the dipstick straight up to release it from the sump.

If you remove the dipstick tube, it's best to have someone helping you when you go to reinstall it. Normally, one would leave the dipstick inside the tube as a 'guide' to reinserting the tube into the sump, but since you're replacing the o-ring at the bottom of the tube, it's not very simple to get it into the correct position unless you have a helper from the top guiding it into place.

 

@NBCat - it's the oil fill tube I need to seal up, not the dipstick. Replaced that a couple of years ago when the bottom of the plastic handle broke off, leaving just one O-ring.

@Addicted2Boost - thank you for that info, exactly what I needed to understand on the oil filler tube. That is a crapload of work just to replace an O-ring at its base. If I decide to break it, will there be any remnants of that locking tab inside the valve cover that can cause issues? I usually don't run the engine cover and have no problem having to hold the riser tube to get the cap off (fortunately the car uses no oil between changes).

I am still not clear on the small vacuum lines at bottom of throttle body, primarily the right side. The brake booster one on left (driver's side) appears to be a fairly standard straight-in connector where I see the release, though getting to it not fun with the coolant hoses in the way.

But the one on the right (passenger side) has a right-angle plastic fitting I cannot figure how to release. It is the biggest leak of the two, and I can pull it in and out a few mm but not sure how to release it. This is the one with a hose that snakes around forward, so between throttle body and rear of intake manifold, then up to a hard plastic line, which goes to 2-3 places. How do you remove that fitting, and will it have a serviceable O-ring or do I need to plan to buy new piece?

Totally agree with your plastics comment, too. Fortunately, our car only has 76,000 miles and has always been garage kept. I also raise the hood every time we get home to let the heat out just to save the plastic and rubber bits.

Doug

 

Sorry, my apologies.

Addicted2boost is absolutely correct that you must remove the cam cover to replace the o-ring for the oil filler.

Post a photo of the fitting(s) you're having trouble releasing.

 

Plastic angle connector vac fitting. Snakes around and connects to hard plastic line that goes to 2-3 places

Brake booster vac line. Those coolant lines really in the way

 

Remove the throttle body but, keep the coolant hoses on for more room. In that top picture, there’s a plastic collar that goes around that angled pipe. Gently but firmly push in that collar with a flathead screwdriver while you’re gently pulling out that angled pipe.

 

Thank you sir! It is definitely easier with the throttle body out of the way. Plus I'd previously read that metal gasket is prone to leak anyway, so may as well do that, too.

I still cannot get the angle fitting out. If I am seeing it correctly, the plastic collar is the yellowish part behind the fitting, which has a black collar molded as part of it (was clear when I wiggled the angle fitting). I am not getting the yellowish collar to budge at all, which is tricky enough since it's pretty much same diameter as the black collar on the fitting. Any other tip/tool I might use besides a flat blade screwdriver?

 

With the throttle body out of the way, look down inside the elbow. You should be able to see the end of the tube. You could use some sort of spray lubricant to help remove it easier. Take some better photos if possible.

 

Ok, here are some close-ups. The yellowish collar around the fitting appears to me to be brass, not plastic. It was quite hard when I put screwdriver to it, with no "give" like plastic would feel. I was able to pull the angle connector out enough that my flat blade screwdriver between the fitting and the yellowish collar. I gently pried on them but no indication it was going to go further. And not much to see from the inside of the intake elbow given how deep it is (unless maybe I had a borescope).

 

Hi,
the trick to removing the pipe is to first depress the black plastic insert into the brass ferrule (and keep it depressed), then pull the pipe out. It is similar to the way push-fit plumbing joins work.

Perhaps this image of the parts will make that clearer:

 

First buy the replacement part and then when you see how it works, you can disassemble the old one without damage!!!!!!!!!!!

Jaguar C2S15816

ETA

michealh you posted a minute before I did.
Good pic!!

 

I concur with Bob and MichaelH, that is a great picture!

 

Thank you for that picture! But now I have two questions:
1. How to depress those retainers given they are on the inside of the throttle elbow? Appears I would somehow have to work a tool in from the back, not depress the outer ring that keeps it from going too far in.
2. Since it is leaking pretty badly, the O-ring in the brass ferrule clearly needs replacing. But that also appears to be on the backside, so it that going to be possible? Or does the brass ferrule need to be replaced in its entirety? And if so, is this a part Jaguar offers?

 

Agree it looks that way, but depressing it does work.

IIRC I fished the old O-ring out from the outside, and used the plastic collar to push the new one back in.
The 3 parts come as a kit under the # that motorcarman posted above (C2S15816) - you won't need the brass ferrule.

Sadly Jaguar has really hiked the price of this - around $25 - but Amazon lists it:

 

Good to know, even though on my car that's not the line that goes to the brake booster (it is on other side).

I wonder if pulling the brass ferrule out is the best approach. And perhaps replacing the whole thing with something simpler/more standard would be better?

 

I don’t see any advantage to replacing the brass part. Just push in the black plastic part as already advised then pull the tube straight out and replace the O ring as needed.

no need to make this operation more complicated than needed.

Z

 

Except easier said than done pushing in the black plastic part w/o breaking it. Then fishing the O-ring from the brass ferrule and getting new one correctly in is no picnic, either. Then you buy the whole thing to replace it. A foreign car mechanic here told me yesterday Land Rover uses same system on water pumps and have to replace entire thing to ensure no leaks. Reminds me of the silly "octopus" coolant hose on our cars, where the needless disconnect fitting leaks and there's a much simpler fix than replacing the entire hose, which will only leak again later.

Clearly not the best way to connect this vacuum line to the throttle elbow since it's leaking big time. Nor do I want to deal with it again. Why not a simple fitting like a metal tube with a small piece of vacuum line to connect to the plastic pipe? Like many German cars do, not to mention how we connected vacuum lines to carburetors back in the day.

 

are you saying you broke the black plastic part ? Or are worried about possibly breaking it ?

Z

 

Worried about it. Not sure what tool to use to push in the collar since it is on the backside inside the elbow. Not much room to get anything inside that elbow, then have enough leverage to depress those 4 tabs.