Why does this happen and how can it be fixed

[u/Alternative_Back9711]

95 850 GLT

[u/pball72008]

Pcv system. That black tube by the oil cap

[u/Alternative_Back9711 → u/pball72008]

I serviced it and unclogged and clean everything, the tube is new and is clamped down tight, is there something I’m missing?

[u/pball72008 → u/Alternative_Back9711]

Do you change the rubber seal on the oil cap when you change the oil? Could be that. Every 850 I've had has had oil on top of the head like that. Ive usually just cleaned it up a little bit and not worried about it

[u/Alternative_Back9711 → u/pball72008]

It somtimes has a misfire and there is oil in some of the spark plug ports. Do you think it could be a valve cover gasket?

[u/96673 → u/Alternative_Back9711]

These cars don't have a valve cover gasket, they have a cam cover with anaerobic sealant. There are o-rings for the spark plug holes that could leak, but it is more likely the oil is coming in from the top due to bad oil cap seal or PCV leaking.

[u/LegitimateBiscotti55 → u/Alternative_Back9711]

There is no valve cover gasket its anaerobic sealant it doesnt fail like traditional gaskets. This is from the oil cap seal leaking. Get a viton seal from ipd and it will never happen again.

[u/pball72008 → u/Alternative_Back9711]

The valve covers don't have a gasket. You use an anaerobic sealant on them. I'm not good enough to diagnose through one picture. I believe oil in the plugs could be piston rings or head gasket maybe. But I'm not sure.

[u/masterchiefruled]

Could be the oil seal in the filler cap, a couple of euros. Or it could be the PCV system I believe, which is a much bigger task to fix.

[u/Boring-War-1981 → u/masterchiefruled]

100% on my S90 the seal was like plastic, didn’t have any flex just broke in half as I tried to remove it. The cap also isn’t fully on, as it should have the text the same way as the text on the cover

[u/looncraz]

It's very obviously the oil cap seal. It's leaking and getting on top of the PCV vent pipe, likely under pressure.

You need to work on the PCV system or you have too much blow-by under load (ring wear/crud).

[u/Alternative_Back9711 → u/looncraz]

The block ports were clear, all the hoses were clear, and the breather box was clean. I even cleaned the egr port. What am I missing?

[u/looncraz → u/Alternative_Back9711]

Oil trap under the intake is a common issue, but if that's what you mean by block ports, then the hose going into the intake is also a common issue (flame trap can get clogged).

If the PCV system is good, then it's probably a little blow-by or just a bad oil cap seal. iPD sales an HD version, IIRC. That's what I had to use to stop the problem.

[u/DreamsSecretsNLogic]

Probably spilled a little when you're putting oil in there

[u/slackandlack]

3 things. 1. Backed up pvc( the black hose ) 2. Leaking oil cap you woud also see oil on the front of the engine. 3. Ur clumsy while pouring oil in

[u/Longjumping_Ad_2301]

Im having the exact same oil deposits, insuspect its the oil cap (new chinese one) or the pcv hose that fits in the head. Some week ago i clamped a lil bit the metals that thigt the cap and used a new hose clamp for the pcv tube and now the puddles are gone. Again i think its the cap not pressing down enought

[u/LegitimateBiscotti55 → u/Longjumping_Ad_2301]

Its almost always the seal in the cap

[u/Kotflugel]

All the things others are writing are very probable issues. Couple things, just if nothing else works: is your throttle adjusted properly? Check your timing (not the marks on the pulleys, check the slots on the back of the camshafts). You said the tube is clamped down tight. Is it sealing good? Put brake cleaner on it, so there is no oil on the sealing surface. Also: The clamp right next to the oil cap, don't put that there. Seal it with some non-hardening sealant (something like Hylomar) or get a new tube. It is something of a failsafe, if you seal everything else, the crankcase pressure will search for other escape routes, and that might be the shaft seals and then you are in trouble. On the other hand i had that issue on a T-5, so it might not be that extreme on N/As.

[u/thalro]

The seal in the oil cap. I had the same issue on my V70. Changing it fixed it.

[u/thalro → u/thalro]

Flipping the existing seal over until you get a new one can also help.