Pit Crew, I'm in the process of going through a hand-me-down Base S-type. The 3.0 is still strong, but suffered a few misfire codes. New packs and plugs solved that,
but also uncovered some oddities.

The valve covers look melted in some spots, include a spark plug tube, and a hold-down point. I'd first misidentified the spark tube as a little o-ring gasket, given it's blackened look.

Any ideas? I'd thought it might be a bad coil pack running current through the cover - but did not see signs of that type of failure --- I did see rust and water in the spark plug hole and so wondering if I'd had a coil/plug current leak conducting through water and finding its way to an outlet ?

 

I've since read Peter's (Peter of Australia!) note regarding these being magnesium vs my uneducated identification (aluminum)..
Still wondering how they're failing in these particular spots. PofA's note is informative, and so I'm reading more on the subject this morning.

I remember reading stories when I was a boy about the Japanese Zero's magnesium alloy construction. Apparently they would "burn like cellophane"
if I recall the article after all of these years. Interesting choice for a hot top end, where fuel is introduced to the sparky-things.

Cheers, and thank you Peter!
KRL

 

Yes a common problem and it would have been so much better if they had used Aluminum instead.
Here is a aftermarket Aluminum one and I would just dump the OEM junk and fix it now. It will only get worse and worse with time.

I mean for $85 each side that's not too bad.

Here is a pair for $215.

If you look there are a number of them out there because it is such a prevalent problem.
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Thank you Clubairth1, I've ordered and standing by for delivery! Thank you! I'll send update pics once fitting.

 

Hi Kevin,
when I saw your pictures, I obviously knew immediately what happened there - but you found my thread meanwhile yourself - G'donya! (That's Aussie-slang for: Good on you!).
Yes, that is galvanic corrosion, where Magnesium is the sacrificial element in the vicinity of aluminium and steel.

Back then I wanted to make sure that when that happens to me again I would not be in a situation, where those cam-covers cannot be bought anymore, thus I bought heaps of those cam-covers on Ali-baba to make sure that my two 3.0L S-Types will not face cam-cover-shortage. I asked the guy on Ali-baba, what the material of his cam-covers is - he was not 100% sure, but he thought that it is still an alloy of several metals, and that they are still containing magnesium.
Yes, I saw that the listing of Clubairth claims that those cam-covers are aluminium, but I would not be surprised, this they actually do not know, and that those cam-covers are coming from the same source where Ali-baba had them from. Thus, even those cam-covers may still contain magnesium, possible less than the OE parts.

It's only 2 days ago that I had one of those cam-covers in my hand again (the one, I mounted on the car - the one under the air intake manifold) as I was looking for a slight oil-leakage - and I hopefully I fixed that leakage. The cam-cover is still looking very good. Worth mentioning: The leakage may have been, where those two half-circles (inside of the blue circles) are:

The picture was taken directly after removal of the cam-cover, i.e. the red RTV silicone is the one I put on last time, but the gray stuff under the half-circles is the OE-stuff.
I removed both half-circles (simply pulled them off with pliers), cleaned everything thoroughly (with wax and grease remover) and then I embedded the 2 half-circles anew in RTV silicone. Maybe that's an idea, while you are at it...
Also note that I did not remove the plastic cowling above (the one, for which you have to remove the wiper-blades), but that is "next-level", as you have to remove 3 connectors and two vacuum hoses from the back blindly, and one of those vac-hoses is one, where you have to press the base-socket towards the air-intake-manifold, while pulling on the tube. If you have never done that before, it is tricky enough when you see, what you are doing...

 

You won't be disappointed and hopefully no more Magnesium! Just too prone to many types of corrosion.
As always follow the JTIS for proper installation.

Do you have the correct shop manual for your car? If not take some time to get one. It's really worth it!
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@ KLinRaleigh:
While I see on your picture that you have already taken the cam covers off, I just wrote down some notes, which might be helpful, for when you try to put everything back together again...:

https://www.jaguarforums.com/forum/s...nifold-288253/

 

We're on the mend. I went the extra bit, and had a vinyl stencil made for the valve cover. New ignition coils and plugs have solved the misfirings and all codes are cleared. I have only the pesky "brake assist failure" lamp to contend with. Sure feels bright under foot I'd have to add. To Peter, hope your ANZAC Commemoration was grand.

 

Looks good. My S-Type actually has a big decorative plastic cover covering all of the cam cover on the left, i.e. on mine that JAGUAR lettering would not be visible...
If brakes do not work properly (=spongy), it's time for a brake fluid swap (the brake fluid "draws" water from the air and does not function anymore as intended.
However, I do not necessarily think that the system would pick up on that and display "brake assist failure". But new fluid is a good idea anyway.

As you seem to have heard about ANZAC day: Do you know, what Australia is celebrating there? Their biggest loss ever in history. It's like Germany having a public holiday on the 9th of May, to remember that they were crushed by the USSR in 1945.

 

Mine does as well, Peter...just the added touch hiding under the plastic cover for my own amusement!