Hi there
I have 2005 Volvo V50 2.4i with 72k. Lately I can hear some whispering noise coming from an engine area. Also check engine lamp is on with code PO171 System too lean (bank1) . Any suggestions? Can it be oil trap ? I changed oil 2 weeks ago. Maf sensor error? Maybe some broken hose?

 

Can it be a vacuum leak?

 

Same car here, same issue. I removed the upper intake manifold and saw that the old oil trap hose was busted, and replaced it. Now it whistles even worse.

I cant get a good handle on how the vacuum is done on this engine, even with the diagrams. When I pull the hose off from the oil trap while its running, the noise is gone and the car runs FINE. As if it doesnt even matter if you have the hose or not.

I'm going to try removing the plastic top from the oil trap and see if there is something there I can clean up, because it had no air pressure at it's hose connector at all, and it should've been pushing oily air out to the head via the hose.

 

Ok thanks.. It seems that the whistling noise was from one of the belts. So it is not related to the check engine lamp. Now the lamp went off so I will wait and see what happen.

 

I had this happen a few years ago. You have to replace the PCV and oil trap. Since this is part of the emissions system, Volvo may reimburse you for the expense, even if your warranty is expired. You may have to call Volvo Customer Care Center (1-800-458-1552)