I know there are a select few cross-breeders over here who have both S-Types and X300's in the stable....or have sold the X300 and obtained an S-Type (this, I can't understand...) and either set will be intimately familiar with the disintegrating cam cover on the X300:
https://www.jaguarforums.com/forum/x...thread-163891/
I have never heard of anyone complaining about it on the S-Type 3.0L, but lo, and behold, look what I found when I set out to accomplish a cam-cover gasket change recently:




A few minutes with a wire brush and drill motor and I could see I wasn't getting where I wanted to go...






Upon inspection of both covers, I thought I had one of six spark plug bores still pristine....however, if you look closely between 2 and 3 o'clock, you'll see the beginnings of corrosion in this one, as well:


Also an attack on 2 mounting bosses:




Clearly, time to break out the sandblaster (as well as the "ROW52" app and start shopping for replacements in better shape)















Arrggh! a breach!!!


And another!!!


I'll attempt to salvage it with the leftover POR15:




Probably take a second coat to fill the larger hole...we'll see once it dries.


On the bright side....only one of the attacks on the mounting bosses have distorted the gasket land. And where it is would lead to an external oil leak rather than filling up the spark plug wells with oil. The corrosion under the coils at the spark plug bores doesn't seem to be a critical area, not letting the wells flood with oil unless you really let it get out of hand and distort the oval gasket groove. Overall, a great disappointment, notwithstanding the design seems to be a bit more forgiving of runaway corrosion than that of the X300.

 

Wow, on first look it seems the coils have an arcing problem and have burned up the cover, but then I see the mounting bosses as well. I'd say it almost looks like a grounding issue to the valve cover caused heavy corrosion, but can't be sure. One thing though is the repair you made is temporary, get another used valve cover. Is the other cover as bad? Also are you cleaning your engine with a corrosive cleaner, the staining on the cover surface is kind of what I've seen with people using mag wheel cleaner on alloy engines.

 

I've not heard of any equivalent issue with any S-Type engine.

 

OUCH.

First I have heard on the S also.

The X300 is well known.

 

I think his pics are from the X300 and NOT from any S-Type.

Bit confusing...

 

Some of it looks similar to heavy pitting electrolysis damage on boat propellers. Edit: add in the cam covers and everything under my S-Type 3.0 hood looks almost new @ 126k mi. but it never was in northern roads salted in the winter.

 

Nope John, sorry to say, every pic in post#1 is of either the bank 1 or bank 2 cam cover freshly removed from my 2005 S-Type 3.0L. All X300 pics are in the link "Definitive....Thread." Sorry for any confusion.

"No" as well, Reno. Engine bay has not been cleaned with any agent - corrosive or otherwise. I do clean the plastic covers with a diluted solution of "Simple Green" rinse with water and treat with Aero 303 protectant, but only when I have removed them to facilitate other maintenance. Unfortunately....this means my S-type engine bay plastics stay pretty buff, year 'round!

I'm sorry crowd, the only hope I can offer you is that the car had it's engine bay washed down weekly with dragon's blood between 2005 when first placed in service and 2009 when we obtained it with 25K miles, and I'm now reaping the rewards....but I highly doubt it.

I may be wrong...but I suspect I'm not the only one running around with cancerous cam covers on the 3.0L. I'll know more once this project is finished and sweet, as the purpose in changing the cam-cover gaskets was to correct a slight oil leak in preparation to sending this one to our daughter in exchange for the 2003 - which has been too long in the field without proper maintenance. (I don't really trust her to keep a close watch on the fluid levels, so don't want to send her a leaker) Anyway, have fit new upper front A-arms recently, currently fitting new plugs, cam cover gaskets, fuel filter and renewing such fluids as merit it. But I digress..once I get the 2003 back, I'll do a similar, though more extensive maintenance and have a good look at the covers on it.

I might add that the 3.0L covers are not the showpiece that the X300 has, front & center, big, bold and beautiful (execpt after it starts to corrode) and I didn't see anything wrong until I pulled the coils (After pulling the intake, on RHS, to boot!) and of course a plastic cover on the LHS. What I'm saying is you won't see this from a casual once-over like you will on the X300.

 

In that case... HORRORS!

I can say that I live in a part of the world where RUST is a nightmare.

My STR isn't affected as regards the kinds of parts in this thread as far as I've seen. Every other part pretty much is, though E.g. took ages to get a nut off the rear link arm.

 

That's a new one on me, Zane. Sure hope your issues are due to something the previous owner did. When I perform the next oil & filter change on my 2005 S-Type (probably in September), I'll try to get a decent look at what may be going on with mine....

Good luck on the repairs....

 

Thanks Jon, and good luck... but..... the mounting boss attack is hidden under a wiring harness retaining bracket (LHS) and you have to pull the coils to see the other....LHS is not bad, but you have to pull the upper intake to get at the RHS coils.

John, from my cursory glance at a breaker-search website this morning, it appears your 4.2L covers are of plastic construction, so you're off the hook! But your comment invokes more bad news... this one has always been a North Texas car..... heck it barely even rains, here! Can't imagine how they'd look in the rust belt.

 

I sure think you've raised a useful issue - and good luck with it!

Because everything here rusts (or corrodes if not rusts) I suppose I just expect a pain (and slap grease on when I remember). I've contemplated sacrificial anodes in case anyone can make suggestions...

Yes, the STR covers are plastic (or some light alloy, but also are not fixed on well so couldn't really corrode on even if they were alloy).

 

@aholbro1 - did your S-Type spend most of its life parked outside? What is the condition of the windshield cowl? Does it still have a good seal?

I wonder if this is related to my rainwater in spark plug wells issue post.

BTW since last posting in that thread I have concluded that the rainwater is in fact coming down into the cam covers from the windshield through the poorly sealing cowl. If the water issue goes unchecked for long periods of time I imagine it could cause major corrosion like this.

Here's a picture of my cam cover...yes the shiny areas are rainwater. I will remove a couple of the coils to inspect for corrosion and post another pic.



@JagV8, still insist there are no design flaws in the cam cover design?

 

Ultrap, almost certain I spy the black death lurking under the boot on that middle coil, but anxious to see what you find. The 2005 has been my wife's daily driver since she acquired it in 2009. So it spends nights and summers in the garage, but school days outside in the school car park (She's a teacher)
Haven't a chance yet to review your cowl link, but have never had a problem with water intrusion at the cowl... and if rainwater has been irrigating the cam covers and plug-wells, it hasn't begat a misfire issue.

 

Well yes really. The rainwater simply should never get there. If you're going to allow rainwater anywhere then many other things are also badly designed - such as the fuel tank. The car doesn't want rainwater in there either. And of course a small number of members have had water in the boot (trunk) but we don't say the modules, rear fuse box, battery etc should all be designed for that. Instead we say to mend the seal and thus keep the rainwater out.

 

Here's the promised picture with the coils out of the way...I found no corrosion around the spark plug bores, only some minor oxidation on the flat surfaces...even though my spark plug wells were filled with water for (probably) a considerable period until finally one of the coils failed, caused a misfire and prompted me to look in there. I have 105K on the odo.

 

Looks good. To make sure, you may want to peek under that wiring harness bracket at the bottom of the picture, just below the bar-code label - That's where I had the boss-attack.
(FWIW, your bracket looks worse than mine, rust-wise, mine being clean... but with a sacrificial magnesium anode nearby...)

 

Just realized I never quite closed the loop on this one. Since I found the 1-Gallon plastic jug so useful while working on the X300 cam-covers, I returned to the well to see if it would bear fruit for the S-Type:



As displayed in the initial post, I had significant deterioration in the Coil collars on both cam covers due to corrosion. To be honest, the boot overlaps the collar "softly" so I don't know that they perform any essential function. I guess it seals against splash-flooding the spark-plug wells, but I believe if you filled the "valley" in the cam-cover with water, it would find its way to the plug wells even in a new, fully intact cam-cover/coil boot combination. Nonetheless, I thought, "I better try to mimic that functionality with some sort of mending..."



I trimmed a selection of water jug necks to account for each knackered coil mounting location:







Then fixed them in place with copious amounts of RTV:









Far from aesthetic, but functional, nonetheless.
To recap, when I found the runaway corrosion, I sandblasted the corroded bits, then treated the sandblasted areas with POR15 Silver (though not the entire cam-cover as my timeline did not allow for a complete cam-cover refurbishment project) Then "repaired" the coil-collars above the spark-plug wells and then refit with new gaskets. After it was all back together (along with several other renewed parts - mostly suspension bits) I tested the thing for a few days then took it off to Monroe, LA to swap for baby girl's 03 which had been in the field too many months and too many miles without a look-see.

One of the issues plaguing the 03 was a right side cam cover leak, so I had the opportunity to repeat. Fortunately, the cam-covers on the 03 were in much better nick. No deformation nor corrosion, though I did find a significant difference between LHS and RHS:





RHS had some sort of black paint that was bubbling and peeling, that was not present on the LHS cover nor either of the covers on the 05. Seemed OEM-applied, as the part-number and barcode were affixed overtop the black paint. In any case, those bubbles and flakes tend to trap moisture and hide all manner of corrosion, so I set about cleaning it off. After I'd stripped it, I reinstalled it "bare" or as near as I could tell, with the same finish as was found on the LHS.

Thus far, the 05 has held serve admirably, though she reports that the right rear window trim departed on the freeway at freeway speed - yes, in fact, that IS the one I bought new clips for and removed and replaced just before taking it to her. So I must've done a bad job. She just completed a 2000 mile foray into Jon and JoycesJag country to interview for pharmacy internships: Drove from BFE, LA to Clover, SC, spent the night at my brother's, then to Durham, thence Salem, VA, Richmond, VA, back to Bro's then back to BFE. Sounds like she's going to repeat this weekend and next week. Interviews in Fayetteville and Salisbury, NC Monday and Friday. We talked about flying/renting but no reasonable fares out of "Nawlins" likely due to Mardis Gras, and if she flies out of DAL/DFW, it would be a 6 hr drive from present position and 8 hr drive back to where she needs to be the following week. That's half of the driving she'd have to do if she just drove to the Carolina's, plus she'd have to fly and rent a car for a week. I concurred with her decision to drive. Wife is worried the car won't hold together. (and she hasn't even SEEN the cam covers...) but then wife hardly ever flies and thinks it would be "relaxing" "restful" and other such rot....but it is really a PITA. Hopefully, she'll be able to bring the 05 home near the end of the month as I suspect its due an oil change soon. Besides, her 03 is nearly ready to go back on-duty, with a fresh DCCV, new Multi-function switch, a solar sensor this weekend, and a few new suspension bits....

Granted, obtaining a set of fully intact cam-covers is on the tick-list, but they are not terribly plentiful and 3.0L S-types are rare creatures in the DFW Pick-n-pull locations. One day, I'll get round to finding a set and changing them out, maybe by the next plug-change, or more likely, the next time the cam-cover gasket starts leaking on the 05, but for now, its ok.

 

Zane,

Check your PMs....

 

Here we are five years on, near as makes no difference, and I've had occasion to go back in this past weekend to replace coils and plugs due to a host of misfire codes on bank one (the odd numbered cyls - the starboard side of the car for you nautical types)
Even so no misfires logged on the even side, Smeghead convinced me I should renew all the coils. FWIW, within the last couple of weeks, I've renewed all coils and plugs in the 05 and 03 with Delphi GN10327 coils and Denso 4511 Platinum TT plugs.

But on to the point of the update. The 05 was the one with the horrific cam cover damage depicted in the OP. I did not observe any additional damage, my plastic water bottle/RTV patches were still aboard, and it was all good, save #6 being somewhat flooded with oil. Yeah, I know...I should renew cam-cover gaskets again - but not yet. The kid will be taking it back to school middle of this week, I'm tired, and it is very hot out....and anyway, EVERY time I order cam-cover gaskets, I manage to get the ones that don't fit. I think it stems from initial order for the 03 many years ago. Something weird about my 03 VIN that it indicates, per most parts-house application charts, a few parts different than the 05, including cam-covers, but actually uses the same parts as the 05. Well, no indication of #6 misfiring, despite the oil, so it shall soldier on. I did not observe any similar damage on the 03 cam covers during a similar service a few weeks ago.

No test drive since fitment, as I still need to accomplish an oil change - in which activity I'll conduct a more thorough search for the flange-nut fixing the starboard windscreen wiper to the actuator shaft - I dropped upon installation and it went down the port side of engine bay, between brake fluid reservoir and block, maybe a bit forward of there, and never found the floor, despite the lower air deflector not being installed! Thank God and Motorcarman for parts cars...I lifted one from the 03 V8 with a knocking rod to finish buttoning up the top side of the engine bay.