850 start up smoke

wildlifeguy · Post by **wildlifeguy** » 20 Dec 2009, 07:37

Season Greeting Everyone! Hope you have a safe and happy holiday where every you may be. No doubt I'll need your help in the future for sure!
With that, wife's 850 blows some smoke at start up, and after idling for 3-5 minutes. after a 3,000rpm for 10-15 sec seems to "clean" things up, but not sure of source.
Driveway mechanic neighbour says possibly valve seats, rings, or Pcv?
I know my previous 940 had a pcv clogging issue and caused the oil filter to loosen and blow off while driving.
He also suggests a compression test as a process of elimination.
Is PCV replacement big job on an 850 non turbo.
your thoughts?

michael

Post by **polskamafia mjl** » 20 Dec 2009, 07:43

PCV issues don't normally manifest themselves as a smoky start up. It is easy to test, however; simply turn the engine on, remove the oil dipstick and place balloon over the end and see if it inflates. If it does then you probably need to do the PCV. If you do get an inflated balloon try cleaning the flame trap underneath that plastic cover at the top of the engine before doing a full on PCV job; the throttle body is also located there. PCV replacement is a doable job, although it may not be the best first project. What color is the smoke?

Post by **jblackburn** » 20 Dec 2009, 13:18

Check the PVC system as described above (just pull the dipstick out once warmed up and see if there is smoke coming out - no need to do the balloon test right off unless you don't see any smoke); then do a compression test to check the rings. If you have low numbers here (<140), try adding a tiny squirt of oil to each cylinder, and then re-do the test. It's possible it may just be a leaky valve guide too, which aren't too much effort to replace.

Post by **Ozark Lee** » 20 Dec 2009, 14:42

The only time I had smoke on startup with a Volvo was back on my 142, replacing the oil seals on the valves completely cured that problem but I understand that they are normally not problematic on the 5 cylinder, white block, engines. The valve guides may be more of a problem than described, Volvo no longer sells them and I don't know what the aftermarket world is doing, not that I would ever put anything aftermarket into a valve train on any of my Volvos.

...Lee