850 cam seal replacement..

[Mike850]

I am going through the car system by system learning it. As far as the PCV system, the only thing I did was clean out the flame trap. It was clogged, so I drilled out the "trap" (the nickel-sized perforated plastic screen) and dislodged all the black build-up allowing it to breathe again. I saw a diagram on fcp groton showing the whole pcv system, but mine is intact. Are there other area in the crankcase ventilation system I need to be checking that could be blocked besides the flame trap? Do these Volvos have replaceable pvc valves like a lot of cars that plug into the valve cover?

[MadeInJapan]

I saw a diagram on fcp groton showing the whole pcv system, but mine is intact.

It could be intact but it could also be clogged inside. The main area that you can take loose and clean out is the PCV nipple on the end of the accordion type hose that goes from the air filter box to the turbo (or if you don't have a turbo, to the throttle body) where the PCV vacuum hose from the oil separator (under the intake manifold) connects. I used a bristly pipe cleaner and alcohol to clean mine.

[xydki]

this may sound crazy, but it worked for me. When this just happened to me 4 months ago, i was about gonna give up on a 260k volvo s70. Exactly as you see in this video was what it was.
I had already looked [desperately, as the leak was too bad] into oil sealants you add to oil. When i finally found what he shows here in this video, i had a long shot idea. I simply pushed the cam seal back in with a stubby screwdriver, working around it from opposite sides, so as to try to get it seated evenly. [this thru the holes you see in the 'sprocket'.] I didn't push hard, just gently. Crosshatch, like wheel lug nuts.
When i had the damn cam seal what i considered 'seated' in its recess, i bought some blue devil 'rear main sealer', and using a small paint brush [which i broke the handle off to make 'stubby'], i painted the blue devil product directly onto the cam seal itself. [this while it was snowing, in a parking lot!] I then bicycled home and came back next day, -leaving some ten hours of 'curing' time. [this ain't something 'blue devil' recommends!]
i then followed the 'blue devil' company's directions, , simply pouring the bottle of 'rear main sealer' into the engine's oil crankcase and running the engine at idle for two hours. Despite some apprehension at starting it, the seal held! After the two hours of the motor idling, i GINGERLY drove the car home, and idled it some wherever i gingerly drove it for a few days. I BABIED IT!
within two weeks i drove it normally. Easy, but normal. A month later, i got on it here and there, -and I still do now! Too soon to say for sure, but i think it's a permanent fix!! May god show this to another who needs it to keep his 'beater' going, -volvo or no!
some points:
blue devil also makes 'oil stop leak', which i think is same formula, but more [fluid and money]. Think i paid $16ish for 'main sealer'. Blue devil's probably 'the best', though other brands are out there. The stuff expands gaskets and seals somehow. This stuff obviously made my 'loosey' cam seal expand enough to snug it firmly in place.
i should note that in this video, the seal seems different than mine was. It seems like if you were to start pushing it into its recess with something, it wouldn't have had as much resistance as mine did. But i can't be sure from a video... Even if it IS looser, you could duct tape a matching cylindrical object over it, or in some way hold it in. If you can get it to stay in after painting the 'stop leak' on it and adding it to motor oil, it could still expand it to hold. But if the cam seal pushes in snugly, so much the better.
My exhaust cam [rear] is a VVVT cam, with that kind of bell shaped pulley. It has no holes in it, as the 'sprocket' in this video does, to place a stubby screwdriver through! Thus, alas, you can't fix it this way. [at least i can't see how.] i think if my rear cam seal woulda blown, i'd a said goodbye to my baby, -cause doing this job 'right' ain't no walk in the park. And i do wrench some...
i also was warned that the pcv system likely caused this failure, and that i had to fix it or more trouble. But i did the dipstick test and the rubber glove test, [thanks robertDIY!], and they both passed. I think the seal just got old and i drove her too hard that night. I lost 3 qts of oil in ten miles b4 i finally stopped. I should change timing belt, [soaked in oil!], but won't, -as it was just changed! Just washed her down good with brake cleaner. [should give it a second wash soon again.]
since this doesn't seem a pcv issue, i would definitely recommend using 'high mileage' motor oil in your old car/ truck. Definitely these volvos! cheap insurance! It's similar to the blue devil stuff, but likely much less concentration. You could even add the blue devil stuff, maybe 1/3 of a bottle every other oil change. Mite be better.
Blue devil raised my oil pressure a lot. At least 1/4! [i got a gauge.] Don't kno why. But no harm i guess, and by golly, it saved my car! It may drop down when i change oil. There have been no side effects from this blue devil oil sealer, as there can be with 'sealers', generally. I've heard of them gunking up things, esp. coolant sealers.
it is possible that the cold weather may have [barely] helped my cam seal 'seat'. If it's summer, maybe you'd put ice [or freon?] in cam seal area... Just an idea. Who knows?