The "valve cover" is the same as the "camshaft cover", right? The engine section of the FSM has no mention of a "valve cover"; but its images of the camshaft covers match the outlines of the valve cover gaskets at rockauto. What the book calls "camshaft covers" seem to me to be what rockauto calls "valve covers". I don't see any room for doubt, but it has happened on occasion, when I've been absolutely sure I was right, that I was absolutely wrong! Am I wrong in this case?
Valve cover same as Camshaft cover?
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Clearly, whether you call it "valve cover" or "camshaft cover", the cover covers both the valves and camshafts in an OHC engine. If, indeed, my center two spark plug boots on each bank are filling with oil because of compromised plug port seals, do I have an important repair issue if there are no other valve cover gasket leaks?
04 Deville, 11 DTS Premium, 00 Deville (sold), 02 Deville (sold)
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I don't see this as being a huge issue... oil does not conduct electricity... it's actually a very good insulator.
I think I'm going to go ahead and replace the spark plug boots in the front bank, since I can't be sure the boot belonging to the carbon tracked plug went back on that plug's replacement--it could have gone on any in the front bank of plugs. If the two center plug boots are filled with oil already, I'll assume, as has been suggested here earlier, that those plug port seals are bad. I'm just trying to figure out how big a deal this is.
What about going forward, though? I wonder about the positive crankcase ventillation mechanism: will the weight of the oil collected around the plug eventually prevent more oil from accumulating around the plug? Will it prevent air under pressure from escaping there? If not, does that pressure leak adversely affect the operation of the PCV system, perhaps promoting sludge?
Thanks, Ranger.
In bold order:
No effect on PCV.
Mechanical repair is the only way to stop oil seepage.
No "air under pressure" involved.
Proper PCV flow and recommended oil changes takes care of the buzzword "sludge". (Open the oil fill cap. Look down in there with a strong flashlight. See anything that makes you worry about "sludge" ???)
Your other post on plug replacement said you had what - 112,000 miles on the engine ??? If that's the case, a bit of oil on the plugs took a LONG time to get there. It's a non-issue. Report back on the amount of oil on the plug shells when you do the new boot install. Then we'll all know.........
I was thinking that "positive crankcase ventillation" meant that there was some small amount of air pressure developed to keep gases moving within the compartments in which oil is lubricating things like the camshaft and crankcase.
Oil cap off, it's clean down there.
In that other post I think I was trying to estimate a reasonable life of the old plugs, using 87000 miles as the last known dealership service by, probably, the original owner. I figure I'm at least the third owner. My odo says almost 214000 miles right now. I don't plan to remove the plugs soon, just replace the four boots. The middle two boots (in each bank of four plugs) were full of oil to about 3" up from the bottom of the boots. The amount of oil in there when I do the four boots soon will say something about how bad the leak is, I guess.
PCV attempts to keep a slight vacuum inside the engine - that's why it's all sealed with O-rings and stuff. The system uses either a calibrated rattle valve or fixed orifice to bleed air into the vacuum side of the throttlebody or intake manifold. That bleed air is calibrated into the fuel/air curves and idle, so you need to get the proper PCV rattle valve unless you have a fixed orifice. In the passenger end of the rear (right) cam cover. A suction side (dirty air) PCV piping leak will set mixture codes.("Cam cover" - I was used to working on old OHC Jaguar engines - that's the nomenclature they used.)
Ok, so the "positive" part of "positive crankcase ventillation" basically means, "yes, there is crankcase ventillation"; and that means that any oil leaking past the plug port seals is a result of the force of the oil splashing around under the cam cover, which means that the more oil that collects around the top of the plug, the less oil will be able to make it past the plug port seal, thus limiting the maximum amount of oil that will collect there over time. Sounds good to me. Thanks, sub.
Replaced the four boots in the front bank. Found only a trace of oil on the bottoms of the two middle boots. So it would seem the plug port seals aren't all that bad off after all. Can't see doing a cam cover gasket job. Thanks to everyone.
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