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Hole in my valve cover (not PCV) and oil leak

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

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Volvomort98
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Hole in my valve cover (not PCV) and oil leak

Post by Volvomort98 »

First time poster, long time reader. Thanks in advance.

I've had the issue of oil under my spark plug cover. I've already replaced the PCV system and oil cap gasket so those common issues are not suspect. The oil is coming from the hole between #3 and #4.

The background: I've been getting a misfire code (#2-5, not #1) for a couple thousand miles. At first I thought it was a vacuum leak as that's what my multiple misfire codes have been in the past but I wasn't able to find a leak. The car ran well with a very occasional shudder at idle. Obviously the car is 22 yrs old so I live with a few quirks.

I changed the spark plugs only a few months ago but in a pinch I didn't get Bosch so I thought perhaps they were already going bad. I went to inspect them and noticed oil had collected (again) under the spark plug cover around #3 and 4. Wiped it up but when I went to pull out #4 spark plug, the well was filled with 1/2 inch of oil. Figured this is why I'm getting a misfire so tried to track down where the oil was coming from- that useless hole between #3 and 4.

When I sopped up the oil I noticed the bottom of the hole looked broken. I don't know if it has always been this way or somehow (I can't think of how) it had been broken recently. I pulled what I think is a small rock out of the hole but it could be a piece of metal. Not sure what to think of this.

Questions:

1. Is this hole normal for the valve cover? If so, what is it, and does mine look damaged somehow? The sharp edges look either broken or machined out. I'm confused at what is happening here.

2. Is the oil buildup in well #4 connected to my misfire? I can't help but think (or hope) it must be.

3. From other reading it sounds like the seal is going bad on my valve cover and pushing oil through that hole. I also have oil crud built up around the seal the circumference of the engine block but this is the only place I'm noticing a full fledged leak. Is the valve cover seal the problem here?
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Re: Hole in my valve cover (not PCV) and oil leak

Post by ZionXIX »

That should be sealed from factory. I have no idea how that blew open. It will either need to be plugged or the head replaced.
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Re: Hole in my valve cover (not PCV) and oil leak

Post by erikv11 »

If it is truly leaking from there, you have correctly surmised that the reason would be the cam cover seal is breached somewhere around the circumference of the hole.

It's unusual for that spot to leak, more commonly the oil comes from somewhere else (e.g. oil cap, hose to the top from PCV) and looks like it's from there. But yes I read your nicely detailed post, maybe it is leaking. I'd get it as dry as possible then jam a wadded piece of paper towel in there, drive it and confirm that it only gets wet from the bottom, or similar.

If it's definitely the source you could (1) live with it, (2) try a ghetto fix with RTV or (3) pull the cam cover and re-seal with anaerobic sealant. If you choose (3) be sure to do a little reading so you don't mess up the cam slots in the head.

There may be a chip from the metal lip but otherwise the hole is not broken on the bottom, that's how they look with the top surface of the head showing. The head is fine, it looks like just the seal between the head and cam cover.
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Re: Hole in my valve cover (not PCV) and oil leak

Post by amblerman »

I am having trouble finding a good clear picture of that hole on a cam cover in its good working condition.
For example here is is on a (presumably good) engine but we can't see it close up.
hole.png
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I suspect, and I can't confirm this, that it's supposed to have some plug in there to prevent oil from leaking out.
In the above picture, nothing is connected to it but it obviously isn't open to the elements like yours is.

However, I have found at least one other example that probably failed like yours did.



in this case someone fixed it by screwing in a bolt.

Then there is this thread : http://volvospeed.com/vs_forum/topic/70 ... lve-cover/

In that last thread the OP even asks "And why the %^&* is there a gaping hole there?" because it seems like the OP has hole in his cam cover just like you. However , no one answers his question and just discuss the common fail points of the oil cap gasket and the PCV hose.
It's almost as if people didn't see his comment.

Very odd. . It's late here but I will look at mine tomorrow. I'm curious now.

Oh.. another thread related to your issue: viewtopic.php?t=74111

This is interesting because there are a lot of threads showing issues with this port/hole but none of them really explain what it is or how it's sealed off when working properly.

This last thread says "In some 93 and/or early 94 setups it was used, but I have sketchy knowledge of those engines, and clearly it is not used on yours. "

Best picture I can find so far of that hole is in this thread. viewtopic.php?t=55337

But again, it's not a great picture. I'll look tomorrow but I am also seeing pictures of some cam covers that don't have that port.
I wonder if it was used in certain years, left in the castings but plugged in some years, and then eliminated in other years.

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Re: Hole in my valve cover (not PCV) and oil leak

Post by Chuck W »

I know I replied to this last night...

That hole is normal and as you guessed, there seal on the cam cover has failed, for whatever reason.

There is another THREAD on this forum discussing the same issue.

I read a long thread on it and searched on some others a while back, but can't remember where it was, but the deal is that on earlier versions of the engine, that port was actually connected to something in the head itself. The turbo models never had this system.
At some point, the head was revised, deleting that port, but the cam cover never was, and thus there is a "hole" to nowhere. (Well, it's blanked off on the head).
If oil is coming out of it, your cam cover seal has failed.

Your "rock" is probably just random debris that happened to wind up on top of the engine, and not part of anything engine-related.
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Re: Hole in my valve cover (not PCV) and oil leak

Post by amblerman »

I find it amazing that they relied on the sealer to prevent leaks on a gaping hole in cover.

I mean I get they would have had to change the molds for the castings but that seems like a better solution than leaving an actual hole in cover. Or maybe press/thread a plugin the hole.
I know.. every option costs $.
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Re: Hole in my valve cover (not PCV) and oil leak

Post by Volvomort98 »

erikv11 wrote: Wed Jul 08, 2020 9:29 pm If it is truly leaking from there, you have correctly surmised that the reason would be the cam cover seal is breached somewhere around the circumference of the hole.

It's unusual for that spot to leak, more commonly the oil comes from somewhere else (e.g. oil cap, hose to the top from PCV) and looks like it's from there. But yes I read your nicely detailed post, maybe it is leaking. I'd get it as dry as possible then jam a wadded piece of paper towel in there, drive it and confirm that it only gets wet from the bottom, or similar.

If it's definitely the source you could (1) live with it, (2) try a ghetto fix with RTV or (3) pull the cam cover and re-seal with anaerobic sealant. If you choose (3) be sure to do a little reading so you don't mess up the cam slots in the head.

There may be a chip from the metal lip but otherwise the hole is not broken on the bottom, that's how they look with the top surface of the head showing. The head is fine, it looks like just the seal between the head and cam cover.
Great idea to confirm this is where the oil is coming from.

I was looking elsewhere and it looks like the seal is failing at multiple points across the valve cover. The bolt near #1 has some oil collected around it. I guess the seal is just old... I'll probably replace the whole thing. Never done that before but I've found quite a few tutorials on this site and thank god for RobertDIY.

@amblerman - thanks for looking up those other threads. That first thread has a lot of information. This pic shows the head section that the cover mates to.
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There's no connection with that hole to the rest of the head. Crazy that that just decided to leave the cover as is when they removed whatever it was initially connected to. If they did that in '93 and mine is '98 that's 5 years of producing that part without making the change... seems like a strange corner to cut for a company that usually over-engineers.
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Re: Hole in my valve cover (not PCV) and oil leak

Post by FLXC90 »

Since we know it is just a minor leak, I suggest tapping a freeze plug or the like into it. It shouldn't have much pressure behind it. and pulling the cam cover is not a trivial matter. If you have no other reason to disturb it, I wouldn't. Then again, if you have seepage in other spots...
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Re: Hole in my valve cover (not PCV) and oil leak

Post by abscate »

Rubber stopper....pop!
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Re: Hole in my valve cover (not PCV) and oil leak

Post by 850oldschool »

Cork + JB weld?
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