Seafoam works.

[marginal]

Tiana, why don't you just take the hose with no clamp on it off and use it?

[marginal]

Tiana.

You can pour it in.
I put it in the glass with sea foam and it worked OK.

[marginal]

I guess you'll have to clean the PCV system ...

[wjhandy850]

The PTC has be clean. That is where the hose from oil separator connects to the air intake going into the turbo. Seafoam will do a good job on removing the hardened deposits that form inside it. The insulated hose and specifically the vacuum hose that runs between the separator and PTC becomes very brittle over time, and must be replaced. I have noticed that on the later models, Volvo has moved to using a metal pipe to replace what is found on 850's The small ports that go into the block are also an area where cleaning it critical. Pouring some Seafoam down into the separator will help clear them out. If it still smokes at the dipstick, I don't know what to tell you. I have same issue, and wonder if it’s the earliest signs of ring wear beyond specs. I can get it to clear using the seafoam to clean the PCV block ports, but it seems to return. I now use the seafoam just prior to oil changes.

[whoa]

Check your compression. Quick, cheap, important. Good compression: no ring problem.

Worn rings on these engines are pretty rare. How much smoke/pressure do you have at the dipstick? Can it blow up a balloon?

If not, my guess is worn/brittle valve stem seals allowing exhaust gases into the oil system. I replaced mine (expensive to have done, not super easy to do yourself) and went from mildly smoking dipstick to vacuum.