Servicing an 850 pcv
 

Does the intake manifold have to be removed to do the standard pcv service?

Yes...

Yes, that and more. See the video at the bottom of this page...

Volvo PCV Breather System Kit (850 C70 S70 V70 Turbo) - 850T200 | FCP Euro

The standard PCV kit is about $154 from FCP. The labor can be accomplished by a handy DIYer, or for about $500-600 at an independent shop.

I took it for granted that the PCV black box had some complicated baffling in it and that's why it caused problems. Then I saw one cut open and there's nothing in there really. You want to make sure the bottom port isn't plugged like in the photo.

If you pull the black box and it's ports aren't plugged you can likely re-use it and just replace the old brittle vacuum lines and if it's a turbo clean out the PTC valve some of the lines run to in the intake.

The problems come when that bottom port the black box uses for a drain plugs up. That was another surprise for me as I thought the box just drained back into the block and dropped into the pan. NOPE ... the engineers designed a passage thats cast into the block and mates with a passage that goes into the oil pan.

The PTC and a shot of that passage in the oil pan that can possibly plug up and cause the engine to push oil past the seals and smoke come out your dipstick or oil fill.

So the deal is, 150 for a complete PCV kit and if the ports plugged and you don't check it and fix it you just spent 150 for parts that won't work. :(

Would it be a feasible / practicable idea to remount a pcv box in an alternative, readily serviceable position in the engine bay and run a oil return hose back to the block.
Obviously all the other hoses would need modifying / rerouting ??
A pcv overhaul would be a lot less hastle without all the stripping down.

Depends on how handy you are. For how seldom you need to do it pulling the intake isn't rally that bad. Maybe the first time ... there are many videos and "How To's" out there to guide you.

If you search "catch can" it can give you some ideas from people who have added them but you need to make room for it, plumb it ....
Unless you need it because you're racing or have a built engine and blowing a lot of oil into the intake with the stock system I don't really see the advantage.

I don't think it's worth messing with. Big thing is with routine LOFs and a good grade oil you don't really have to do it again unless the hoses start to get soggy or brittle and you don't really need to do the box as it shouldn't clog if you're doing the LOFs in a timely manner. If you're using good quality hose or better yet substitute silicone, it could easily be 5, 10 or more before you have to go in there again unless you have a knock sensor or starter fail :-(

Just my 2 cents.

Kiss4aFrog - On further reflection I think you are right.
From an individuals angle pcv issues are likely to be minimal and far between.
Having read dozens of posts lately from far and wide from so many owners, and the way pcv's seem to be an issue for each, one kind of gets the false impression that they are a major and constantly recurring issue with Volvo's.
Your '2 cents worth' does put things back into perspective.

Keeping one's engine maintained with quality oil of the right grade, clean and sludge free with regular filter changes would minimise blockages considerably.

Exactly. I've seen people here recommend replacing the PCV system every 70,000 miles. There is no need for that if well maintained. My S60 (similar system) has 110k and the PCV is fine. Not even any oil seeping at the turbo like most others. But, I change my oil every 3-4k.

Like ES6T said, if it's maintained I don't think it will be a problem for a lot of miles. How many, 100 or 200K would be reasonable. If you look at the inside of that black box there really isn't much to plug.

I'm pretty sure mine and a lot of peoples become a problem because people forget or neglect the oil changes as the car ages. I knew people who would come in and ask for three quarts of oil and it was because "that light" came on again and they know from experience it takes three to get it back on the stick !!!!!!!!!! These were older cast iron V8s and they were more forgiving but it's the way people look at it. Pay 25 bucks for an oil change or go have a burger and a couple beers . . . burger and beer. get the LOF later.

Or, it's leaking pretty good and you're dumping in a quart every other week, can't afford the repair to get it fixed you figure you've changed the oil every three months as you've added five or six quarts. :(
I'm pretty sure the single mom who owned my 850 thought that way. Short on money you cut whatever corners you can.

The owners manual recommends that it be checked every 60,000. The reason it's a big deal and buzzing all the time is people get these cars and it has NOT been cared for since new. So you have a system that has a broken vac somewhere which causes other problems in the system.

If the lines or elbows get hard and crack, split, etc., it will need to be serviced or replaced. If the thing fails the test, replace it. I'm not sure changing oil ever 1,000 miles will stop an elbow from getting hard and splitting. Heck, I have seen 16 month old elbows melted away (after market parts). So, that system was on it's way out after only 16 months.

I wasn't talking about split vacuum lines. I was referring to replacing the breather box. Any split vacuum lines should of course be replaced as needed.