Very common on these Volvos. Replace the PCV Box (Oil Trap Box) on top of engine. you should be able to pull the dipstick out and noise goes away. There's a diaphragm inside the Box that fails causing the issue.

 

Is it possible to have too much vacuum in the PCV system?

Yes! In your situation, the engine is trying to suck air in any why it can. Air and grit gets sucked in through the engine oil seals, contaminating the oil and damaging the seals. Get the PCV box replaced right now.

 

Thank you both! I’ve ordered a replacement PCV, which should arrive in a couple days.

 

Yes, almost textbook 3.2 PCV. They have been going between 100k-130k miles for many owners. It is a very easy change which takes all of 10 mins. Learn more about this and other maintenance items that may pop-up soon in your 131k mile 3.2:

The 3.2L (B6324S) Engine: The Good, the Bad, and the...

I figure we could get a 3.2L thread going. I'll kick it off, but hope others can add to it. I've only had my 2011 for a year now, but I've read as much as I could in VIDA and elsewhere. A great debt of thanks goes to Swedespeed forum members who have helped me out over the past year. If you've...

www.swedespeed.com

 

Had the same problem. I changed mine at 88K. Easy job and problem is now gone. https://www.amazon.com/gp/product/B00NT9K874

 

i had this problem on my 2012 and replaced the pcv box. the check engine light comes on and off intermittently. i still have suction under oil cap and dipstick tube with evidence of oil burning on my rear bumper and intermittent smells of oil burning as well. anyone point me in direction of further repair?

 

I'm having a weird problem with my wife's 2011 XC90 3.2 with 131k mi. Recently the vehicle started making a high pitched whine when idling or when the throttle is closed. The engine seems to idle a bit rougher too and I am getting a few error codes:

ECM-P017100 System Too Lean (Bank 1)
ECM-P017400 System Too Lean (Bank 2)
ECM-P042000 Catalyst System Efficiency Below Threshold (Bank 1)

This one just appeared today:
ECM-P227200 O2 Sensor Stuck Lean - Bank 2, Sensor 2

For the first two, the diagnostic info suggested a vacuum leak so this weekend after changing the oil I tried visually inspecting the hoses and fittings, spraying soapy water on the connections and listening to various components with a long hose held to my ear, but couldn't find anything. The whole intake sounds about the same. The noise might have been louder around the two actuators on the intake manifold, but I'm not really sure.

Not sure what else to do, I tried the glove test and when I started the engine the glove was quickly sucked against the screen in the oil filler. I was actually worried it might get sucked in and the glove ripped while I was trying to remove it while the engine was still running.

I have vida/dice and tried clearing the codes, but they come right back. The slight roughness at idle is consistent, but the high pitched noise only seems to occur after the vehicle has been running for ~20 min or more team building costa del sol. Today when the noise occurred I tried removing the oil filler cap and could turn it, but there was too much vacuum and I could not pull the cap off (when the engine is not making the high pitched noise I can easily remove the oil filler cap). If I pull out the dipstick that seems to let enough air into the crankcase and I can then remove the oil filler cap. Removing the dipstick or oil filler cap also makes the noise go away. Is it possible to have too much vacuum in the PCV system?

When the system is making the high pitched noise, shutting off the engine makes the noise fade after a few seconds. It doesn't immediately stop when the engine stops.

One other odd thing is that when the engine is idling if I tap the accelerator I can hear a brief pffft kind of sound coming from somewhere in the engine/intake area. Maybe this is normal, but I hadn't noticed it before today.

I have the VTT valve cover with a -8 line into catch-can then out of catch-can to a check valve flowing into a -8 on the intake manifold. The car is pulling tremendous amounts of vacuum that the car won't idle without the oil cap off (which makes sense because the system is closed) When the oil cap is off I still measured 25hg of vac at idle. I also have the VTT vac relief fitting that does not seem to do anything. What is the best way for me to get vac relief? I thought about getting the VTT crank case breather and taking out the ball to just have a filtered vac relief, are there any other options? Do I replace my check valve with a PCV valve to limit the amount of vac?