I recently determined that the PCV system on my '98 V70 GLT was clogged. One of the indicators I found in several places was visible 'fumes' from the dipstick tube while the engine is running.

Well, I replaced the PCV system several weeks ago and I can still see the fumes. I may be fooling myself, but it seems to be less visible, but it's definitely still there. Can anyone give some insight as to why this would be?

 

I did mine on a S70 and seen fumes for about 1,000 miles. I believe it went away but as long as it's not that strong/thick I wouldn't worry about it.