question about oil leak from vent hole in top of cam cover
 

I've searched several of the volvo related forums & on google for this issue, found a couple of people that experienced it, but no good answers due to cause, so hopefully someone here will be able to help.

Recently, my 1998 V70 AWD burnt a valve; i have just finished reassembly after replacing both exhaust valves in cylinder #4. Followed directions per VADIS, with some help from various postings on forums. Cleaned oil trap/PCV, replaced hose assembly from intake hose to oil trap before reassembly. Before reinstalling the head & cam cover, all oil passages & drains were verified clear/unplugged. The headgasket used is a Goetze, from the Fel-Pro gasket kit I used, and appeared to be constructed identically to the one that came off.

Everything seems working correctly, car runs fine, no codes. However, there is what appears to be a vent hole in the top of the cam cover, near spark plug #4, that fills with oil. Eventually (within the time it takes the engine to get to normal operating temperature), it overflows into the spark plug area, and if left, out the rubber/plastic hole filler above the turbo. I can shut off the engine, remove all oil from this hole, then restart the engine, and watch it slowly fill again.

To me, this seems like a drainage issue. I did seem to have this problem to some extent before, as every time i have had the spark plug cover off, I've cleaned oil from the area. It seems worse now, however.

Any ideas on if this is a drainage issue, or not? And, if it is, would there be a way to resolve the issue without removing the head again?

Thanks for any help!

Is the cam cover sealed good on that area?

I'm not 100% certain, but it should be - the liquid gasket material was applied per directions, and bolts torqued as specified. Is there any way to check, short of removing it?

Not really any way to check sadly.
It is like an extra hole with a screw hole next to it correct?

correct - it looks like it may have been intended to be a vent of some sort, and has a small tapped hole on either side of it.

Do you think that improper sealing of the cam cover is the likely cause? I would rather that be the issue than something further down, less work and money involved that way :)

I have seen where a couple of people have just plugged this hole, but I'm afraid in my case that the oil will find another path if i do this. What are your thoughts about just plugging it?

Try plugging it and see what happens.
Also with the car running make sure exhaust fumes do not come out. If they do then the head is for an air pump car and there should be a pipe in that hole.

I tried plugging it, took a 7 mile trip, with no issues Saturday. Took a ~55 mile drive today (about 1/2 Interstate), and when I got home, oil was coming out from under the plug, and had come out the spark plug gally plug/opening in the rear (over the turbo). I'm going to try a different plugging solution, as I didn't really like the first setup.

There does not appear to be any fumes coming from the hole, and it does fill more slowly than it had before. However, due to other indications, I think the engine in the car has been changed at some point (the engine does seem to be correct for the car, though). Which cars had this air pump? I'm assuming this is different from the "secondary air system"?

The cars with air pump means the "secondary air system".
They started in 96 and stopped in 98.

Mine does have that, but it seems to connect only to the downpipe just behind the turbo, and based on the VADIS picture of the system, does not seem to be missing any parts other than the mounting bracket attached to the turbo. (air pump, two hoses, one to air cleaner, other to "non-return valve", which connects to exhaust via hard metal tube)

thanks for the help, btw - I do appreciate it.

Ok on some of them they have a different setup. Look up an air pump system on a 960 and you will see how the other setup runs. Maybe you can get a pipe from the other setup and screw it in there and pinch off the other end or have it welded shut.

thanks for the tip - i looked at the 960 diagram, and saw the piece you're referring to. If my new plugging attempt doesn't work out, I'll see if i can't locate one of those pipes and try that.

I couldn't find any of the 5-cyl. engines that had that setup when I was looking through the diagrams - do you know if it was only the 6-cyl. 960 that had that setup?

Some of the turbo 850's and S70's had them but I believe it all depends on the emissions code.

thanks for the help, tech - I looked at the '97 850 specs just before you posted that & found the diagram you were talking about.

However, I've since taken the cam cover off, and it appears your first suggestion was correct - it didn't seal correctly. I've gotten everything cleaned up again, and I ordered some of the oem-type sealant from FCPGroton, and was about to start reassembly but I found something about the application of the sealant I wanted to ask about. The roller I used before is a small (~3") paint-type roller; would one with the sponge-type roller work better? Or does it not matter?

It really does not matter I have used both with the same results.

thanks again for the help, tech - finally got everything finished up Wed., took a 400 mi round trip yesterday w/ no issues, other than blowing vacuum caps off the vacuum tree (which it has only done before when i had the vent hole in the head plugged).

Glad it is better.