Hi everyone,

I have a question. So after replacing valve cover gaskets, spark plugs, transmission cooler lines and power steering lines 3 months ago. Along with fixing the AC system, i thought I would be trouble free for some time. Anyhow, today I decided to take the kids to get Ice cream and stretch the cars legs. I maybe added 5 miles round trip. When I pulled into the garage, I noticed a significant puddle of oil on the driveway. I looked under the car and sure enough there was a puddle of oil on the garage floor too. I popped the hood and oddly enough I have oil sprayed on the front part of the valve cover and it is puddled on the side of the block above the intake manifold. Needles to say, I am frustrated and feel like driving the car into a nearby lake out of pure frustration... It is always a PITA adventure with the Jag. I am enclosing a picture of the leak from the top. Do you guys have any idea of what would cause oil to leak from here? This is a 1994 Aj6 XJS.



Thanks,
Dan

 

Dan,

I'm thinking perhaps you've not quite fitted the camera cover gasket properly and it's got distorted at that point where the oil is leaking.

Good luck

Paul

 

Hi Paul,

Thank you for the reply. I had my local Jag shop install the Valve cover gasket 3x. Each time a new gasket was installed because it looked like it was leaking. However, how would the valve cover spit the oil up towards the hood and the top of the valve cover?

Thanks,
Dan

 

Its the oil pressure. You have a pitted surface, pin hole sized leaks have plenty of spray power. Ever stand over your toilet and sprayed **** all over the place? Same thing, pressure. Especially if you fell asleep after sex, and experienced the split stream. Anyway, I think you have a warp or pit that is allowing it to seep. At least you had a good drive with your spawn and they will always remember the smell of oil burning on a jag block, back off the bolt in that area a hair. Clean and drive. If it slows leave it alone for a few more drives. Then tighten a bit, just a hair

 

LOL! That was an interesting and entertaining read. Thanks for the recommendation. I will give it a try.

Dan

 

What is going on with the shop you are using???
Did they give you some sort of idea why it needed repeating?
What was the time frame for the three gasket installs?
Cam cover gasket is a fairly easy job and you can be sure it was done right.
How did they address the half moon seals?
Did they do a crank case pressure check?
How about compression????
Is the technician a relative?
If not fire the shop, buy some tools and start reading.
Don't go to YouTube for answers to this, It's very basic.

 

When you did the Camcover gasket, did the seals of the 14?? retaining bolts gt replaced?

If no, panic not.

DO NOT go and tighten those bolts, as they are a shanked bolt, and will only tighten to a SET length.

What I did to the '40's, and the AJ16, was to rummage in my stash of stuff, and found some 1/32 thick fibre washers that slid over those bolts, Removed the Jag seals etc, slid the fibre on, then the Jag stuff, refitted. That gave the "set length" of those bolts a slightly tighter "crush" on the gasket etc.

I also used a smear of Grey RTV on that gasket, just because.

DO NOT Gorilla tighten those bolts, they will NOT tighten down anymore than the pre-set shank, All you will do is SNAP the threads off in the head, and then the happy vibes will be gone.

 

I don't recall if the retaining bolt seal gaskets were replaced. Thanks for the info.

 

​​​​​​Funny thing is the "shop" came highly recommended to me from this forum. I have always worked on my own cars, but never the Jag. So when i took it in to have the AC repaired and the trans cooler and PS lines replaced, I figured the cam cover would be an easy job just to have them complete. Needless to say, the shop dropped a poll jack on my car and had to repaint the front fender. Every time I picked up the car and reached home, I noticed the leak and had to call the shop to get the valve cover replaced. So each time it did not go past a day with the new gasket. The half moons were replaced with the factory rubber ones. In all fairness the shop was interested in making it right, however, clearly that's not how it turned out. I'm not interested in taking it back to them, in fact I am beyond disappointed. Hence my post on here, wondering if perhaps I am missing some kind of High pressure oil line that runs along this area that was possibly leaking, but I guess not. I've never had such a difficult experience with a valve cover gasket.

 

I'm not sure how there is oil pressure on a valve cover but there is crank case pressure. This ia a good tip ( above). Have him check the PCV and vent. This will only spray when there is pressure. You should be able to witness while running after a good hot run. Opening the oil fill cap will relieve it.

BTW changing the valve cover gasket 3 times should be a clue that something else is wrong.

 

Does the AJ6 have a PCV? The AJ16 does not. There's that egg shaped plastic thingamajiggy that branches off of that camcover hose.

This does seem like there is something creating an excessive buildup of pressure in the engine that is not relieved. That would explain why you've had to replace this gasket several times. Please check the hose that connects to the camcover and see if you can blow through it....easily. It's a big hose, so there shouldn't be any resistance.

 

I don't know much about your particular car but the oil in that leak is going UP, against gravity, and I don't think I've ever seen that before in a weeping or leaking gasket at a valve cover... Without wanting to sound overly dramatic,,, that's light but 'explosive' pressure. Something somehow is allowing too much pressure to grow inside of the cover. I think they have mixed up the routing of some of the hoses or the venting setup.

Can ya take a couple of shots of the cover/engine from a distance and maybe some of the more experienced folks here can see IF there is a line or two that is amiss, reversed, mixed up, one to check for a clog, or sumpthin???

Brah,,, don't think of giving up on THIS car because of a bone headed mistake by a shop guy....

 

I agree that I have never seen oil travel up, unless it is high pressure or pressurized. This has looked very suspicious to me and such an easy task is turning into a mission now. Here are multiple pictures of the area.
*Update, so I was tinkering with the PCV hose etc and decided to pop off the oil cap. When i turned it, the cap would not come off. It felt as though maybe I hadn't turned it enough or maybe the top was just turning, but the cap wouldn't come off. I grabbed a small 45deg bend screw driver and slightly gave it pressure and the cap popped off. As if it was sealed on there by pressure. Could this be more closely related to a PCV issue?

 

Aan easy way to check this is start the engine, drive it around a bit, stop, put it in Park and leave it running and then crack the oil cap and lift a little. The keeps oil from splashing out. If you get tons of air flow coming out, you found a problem. If you hear air rushing in, you found a problem.

 

I have a clean engine bay too, but the red body make it look like more exotic. Beautiful

 

Hi JAAA6

Sorry to hear you are having probs but giving up or losing interest, is not really an option so I think you need to bite the bullet and do a Compression Test, or you could easily end up chasing rainbows

I did that on my AJ16 when She wouldn't start, after I'd tried everything that I could think off, where I have to tell you here and now that I felt sick with worry and anticipation at the looming prospect that one of those Six Cylinders would fail

Where much to my Surprise and delight She passed the Compression Test with flying Colours

Testing the Compression is dead easy and something you could easily do yourself with the help of a Mate to Crank the Engine over on the Starter while you are holding the Compression Tester in the hole

A Compression Tester is only about $20 and you would do well to get yourself a Magnetic Pick Up Tool to lift out the Spark Plugs once you've unscrewed them, nothing Complicated, its really a 'Walk in the Park'

How to do that is all here on page 95 of my restoration Thread complete with Shed loads of Photos to show you what to do and for anyone else who's having problems of a different kind there's loads of other Stuff that may be useful like removing the Fuel Rail and Changing the Injectors and the Fuel Pump

Plus every Trick in the book I used to try and get her Started including Changing the Crank Position Sensor, which is only a 5 Minute Job you can do by the side of the road (once you know how) providing you happen to have a Spare one to hand

Doing a Compression Test on an AJ6 / AJ16 Engine plus loads of other stuff

 

Thanks for the pictures.... I would be interested in the line traced in RED below.... On the V12 there is a vent similar to this that sends oil filled air (cranck case air) back into the intake to be burned, to relieve pressure (PSI) buildup in the engine (actually create a vacuum on a good day) and as an emissions requierment. Most v12 owners have removed them all together. Im not sure, and again I hope someone who is more familiar with your car will help me here, but perhaps there is some sort of "filter" (similar to the v12) that kinda sifts out the larger oil droplets before they make it unfettered completely to the the intake,,, drowning things.

Remove that large clamp on the hose at the cam cover and see what you can see. Blow thru it and make sure that it is unobstructed. Remove it all together! Also, I am sure there must be some kind of UNSEEN baffle and sets of corners on the underside of the cam cover which prevents oil splash from the underside of the cam cover to FREELY travel into that line so I think (repeat THINK) you aught be good starting the car with that hose removed? Im not sure if starting the car with it removed will allow a **** ton of air into the intake driving idle THRU the roof so just be ready to turn it off it the idle SHOOTS on start...

Problem is, if there is NO vent in the engine and crank case it drives up inner engine pressure (how hi I do not know - it is beyond my level of experience with any car) high enough to PUSH oil out of all kinds of nooks and crannies. front and rear seals, weak gaskets - and stuff like that. Ya might be losing oil in a few different places.

 

Got to say I agree with JJJ, it looks to me like unrelieved crankcase pressure. I would check the PCV system for blockages etc.

 

*Update** I've been rather swamped with work, but the plan is to replace both the PCV valve and the valve cover gasket (Again). However, this time instead of taking it to an independent shop, I am going to replace it myself. I have done this job many times on other cars i've owned, just not the Jag. I am very upset with the shop that did the work, disappointed as well. I'm not really sure how he works on Ferraris, Masserati's and others that are parked in the lot. It blows my mind. Anyhow, I will update the post once I complete the work.

JayJagJay, thanks for the motivation...

Dan

 

Before you start replacing things diagnose and find the leak. If you had a pool of oil under the car it should be pretty obvious where its leaking whether its actually from under cam cover gasket or somewhere else. I have a feeling it not necessarily leaking from the cam cover, unless you have a completely blocked hose going from the cam cover to rubber elbow. I've had mine replaced recently and accidentally at first kinked one of the half moons at the back and I've only noticed after driving 20 miles and it still didn't leak that badly to create a pool under the car.
I would be looking at the front main seal, oil cooler hoses or adapter under oil filter, oil filter housing itself and oil pressure sensor(right to oil filter), any of them have way more potential for creating oil puddles under the car and if any of them leaking oil can certainly find its way everywhere under bonnet, especially when you drive the car.
I'd start with wiping down all the oil, put the car on axle stands, start it up, leave it running for 20 minutes and then get a bright light and start looking, hopefully should be pretty obvious where its leaking.